天堂洞, 峰牙-格邦国家公园, 越南 Paradise Cave, Phong Nha-Ke Bang National Park, Vietnam (© Pakawat Thongcharoen/Getty Images)

地下天堂 Underground paradise

天堂洞, 峰牙-格邦国家公园, 越南

天堂洞给人的第一印象极其震撼，游客一踏入其中便会为之惊叹。这座巨大的石灰岩洞穴位于越南中部峰牙-己榜国家公园深处，该地区以崎岖的山脉和无数隐秘的洞穴而闻名。天堂洞绵延超过19英里，是亚洲最长的旱洞之一，其规模之宏大令人叹为观止。高耸的洞顶俯瞰着步道，富含矿物质的水流经数百万年形成层层叠叠的图案遍布洞壁。

到达洞口需要先攀爬一段林间小路，然后下降到凉爽的空气中。洞内，柔和的灯光映照出高耸的石柱、精致的钟乳石和宽敞的洞室，令人感觉格外开阔。一条木栈道安全地引导游客，并让他们近距离欣赏这些奇特的地貌。这个庞大的洞穴系统只有一小部分对外开放；大部分区域都延伸到已开发的步道之外，至今仍受到保护，不对外开放。宁静、宽敞而古老，天堂洞为人们提供了一个静谧的机会，窥见该地区深远的地质历史。

Paradise Cave, Phong Nha-Ke Bang National Park, Vietnam

Paradise Cave makes a powerful first impression the moment visitors step inside. This vast limestone cavern lies deep within Phong Nha-Ke Bang National Park in central Vietnam, a region marked by rugged mountains and countless hidden caves. Stretching over 19 miles, Paradise Cave is one of Asia's longest dry caves, and its scale is immediately apparent. High ceilings rise above the walkways, and layered patterns formed by mineral-rich water over millions of years line the walls.

Reaching the entrance involves a short forest climb, followed by a descent into cooler air. Inside, soft lighting reveals towering columns, delicate stalactites, and broad chambers that feel surprisingly spacious. A wooden path safely guides visitors while offering close views of the formations. Only a small section of this extensive cave system is accessible; most of its length extends far beyond the developed walkway and remains protected from tourism. Calm, spacious, and ancient, Paradise Cave offers a quiet glimpse into the region's deep geological past.

佩吉角灯塔, 大西洋海岸, 新斯科舍省, 加拿大 Peggy's Point Lighthouse, Atlantic Coast, Nova Scotia, Canada (© Prashanth Bala/Shutterstock)

海边的宁静 Serenity by the sea

佩吉角灯塔, 大西洋海岸, 新斯科舍省, 加拿大

佩吉湾是新斯科舍省崎岖海岸线上一个迷人而小巧的村庄，展现了海滨生活的一角。村里最著名的地标是佩吉角灯塔（也称佩吉湾灯塔），它最初建于1868年，后于1915年被现在的灯塔所取代。一个多世纪以来，它指引着船只穿梭于变幻莫测的大西洋，成为海岸生活永恒的象征。周围的景色，海风吹拂，波涛汹涌，仿佛时间在这里停滞。

这个温馨多彩的小村庄，海岸线上点缀着古朴的房屋和当地特色小店。佩吉湾以其宁静祥和而闻名，同时也拥有充满活力的艺术氛围，画廊和工作室林立，展现着当地的创造力。这里是海鲜爱好者的天堂，附近的餐厅供应最新鲜的龙虾料理。来这里旅行不仅仅是一次观光，更是一次放慢脚步，享受海岸生活简单美好的邀请。

Peggy's Point Lighthouse, Atlantic Coast, Nova Scotia, Canada

Peggy's Cove is a small yet captivating village on the rugged coast of Nova Scotia that offers a glimpse of life by the sea. The village's most famous landmark is Peggy's Point Lighthouse—also known as Peggy's Cove Lighthouse—first established in 1868 and replaced by the current structure in 1915. For over a century, it has guided ships through the ever-changing Atlantic waters, serving as a timeless symbol of coastal life. The surrounding landscape, with its windswept beauty and crashing waves, feels almost untouched by time.

The cozy, colorful village is dotted with quaint homes and local shops along the shoreline. While known for its tranquility, Peggy's Cove also boasts a vibrant arts scene, with galleries and workshops celebrating local creativity. The area is a seafood lover's paradise, with nearby restaurants offering the freshest lobster dishes. A trip here is not just a visit—it's an invitation to slow down and enjoy the simple beauty of coastal life.

洛根溪吊桥，西海岸步道，加拿大 Logan Creek Suspension Bridge, West Coast Trail, Canada (© Tandem Stock/Adobe Stock)

凌驾荒野之上 A step above the wild

洛根溪吊桥，西海岸步道，加拿大

沿着加拿大温哥华岛西南部偏远海岸延伸的西海岸步道，是该国最具传奇色彩的徒步路线之一。这条步道位于 太平洋沿岸国家公园保护区，全长约47英里，穿越雨林、沙滩和岩石海岸线。该步道始建于1907年，最初是一条为海难幸存者设立的救生通道，沿线海域曾被水手称为“太平洋墓地”。

步道上的现代设施之一是洛根溪吊桥——也就是今日画面中的主角。这座结构壮观的桥梁在提升安全性的同时，并未削弱徒步的刺激感。这座洛根溪吊桥桥长约371英尺，悬挂在下方溪流约130英尺高的空中，取代了原本陡峭的木梯下行路段——那段路即使对体力充沛的徒步者来说也极具挑战。穿越吊桥时，可以俯瞰脚下远处茂密的森林和奔腾的溪水，视野开阔而壮观。

这条路线穿越胡艾阿特族、迪蒂达特族和帕奇达特族原住民族的传统领地，为徒步体验增添了深厚的人文内涵。对于热爱探险的旅行者来说，西海岸步道展现了加拿大原始海岸风貌的真实魅力。

Logan Creek Suspension Bridge, West Coast Trail, Canada

Running along the remote southwest coast of Vancouver Island in Canada, the West Coast Trail is one of the country's most legendary hikes. Located in British Columbia's Pacific Rim National Park Reserve, the trail stretches about 47 miles through rainforest, beaches, and rocky shoreline. It was established in 1907 as a lifesaving route for shipwreck survivors along what sailors once called the 'Graveyard of the Pacific.'

A modern feature is the Logan Creek Suspension Bridge—seen in today's image—an impressive structure that makes the journey safer without dulling the thrill. The bridge spans roughly 371 feet and hangs about 130 feet above the creek below, replacing a steep ladder descent that challenged even strong hikers. Crossing it offers wide views of dense forest and rushing water far beneath your boots.

The route passes through the traditional lands of the Huu-ay-aht, Ditidaht, and Pacheedaht First Nations, adding cultural depth to the experience. For adventurous travelers, the West Coast Trail delivers a true taste of wild coastal Canada.

坦噶尼喀湖，非洲 Lake Tanganyika, Africa (© BEST-BACKGROUNDS/NASA/Shutterstock)

当水划出界线 When water draws the line

世界水日

今天是世界水日。该纪念日由联合国于1992年设立，并于次年首次举行。人类已不能再随波逐流——我们必须守护那些维系生命的水流。在非洲东部大裂谷的坦噶尼喀湖，几乎最能体现这种紧迫感。从太空俯瞰，它宛如一条长约420英里（约676公里）的蓝色丝带，连接着坦桑尼亚、布隆迪、刚果民主共和国和赞比亚。在湖岸边，它则是一处拥有约1000万年历史的裂谷盆地，由地壳缓慢张裂形成。

坦噶尼喀湖最深处超过4800英尺（约1460米），储存着地球未冻结地表淡水资源的约16%。它养育着数百万人，提供饮用水、食物来源以及交通通道。湖中生活着色彩鲜艳的慈鲷等特有物种，这些在世界其他地方找不到的鱼类，使湖泊深处成为一座“活的进化实验室”。

从空中俯瞰，这座古老的水库似乎坚不可摧；但近距离观察，它却正面临水温升高、污染和过度捕捞等威胁。今天的图片提醒我们一个现实：水不仅滋养生命，也引导着生命的方向。而每一滴水，都值得我们去守护。

World Water Day

Today is World Water Day, declared by the UN in 1992 and first observed the following year. Humanity could no longer drift along—we had to safeguard the very currents that keep us alive. Few places capture that urgency like Lake Tanganyika, in the Great Rift Valley of eastern Africa. From space, it's a roughly 420‑mile ribbon linking Tanzania, Burundi, the Democratic Republic of the Congo, and Zambia. At the shoreline, it's a 10-million-year-old rift basin, formed as the Earth's crust slowly pulled apart.

Tanganyika plunges over 4,800 feet, storing roughly 16% of Earth's unfrozen surface freshwater. It sustains millions, supplying drinking water, nourishment, and transport routes. Species like brightly colored cichlids, found nowhere else, turn the lake's depths into a living laboratory of evolution.

From above, this ancient reservoir looks unshakable. Up close, it's vulnerable to warming waters, pollution, and overfishing. Today's image is a splash of reality: water doesn't just sustain life—it steers it. And every drop is worth fighting for.

莱泰亚森林，多瑙河三角洲，罗马尼亚 Letea Forest, Danube Delta, Romania (© Wild Wonders of Europe/Widstrand/Nature Picture Library)

根系自由生长的地方 Where roots run wild

国际森林日

如果地球有一支“维护团队”，森林一定会冲在最前线。它们吸收碳排放，减少水土流失，保护生物多样性，影响降雨，并帮助维持清洁的水源。目前，森林仍覆盖着全球约31%的陆地面积，但其持续减少表明，这些自然系统正变得愈发脆弱。大片森林仍在被开垦，用于农业生产、基础设施建设和资源开发，使生态系统以令人担忧的速度不断削弱。

国际森林日定于每年3月21日，由联合国于2012年设立，旨在提高公众意识并推动切实行动。各国政府、组织和社区通常通过植树造林、分享研究成果以及推广可持续森林经营等方式来纪念这一天。为什么这一天如此重要？因为森林的健康状况直接关系到气候稳定、生物多样性保护以及全球粮食安全。

今天图片中展示的罗马尼亚莱泰亚森林，正体现了保护行动的实际成果。它是多瑙河三角洲生物圈保护区的一部分，生长在由水流与风力长期塑造而成的海洋沙质地貌上。保护像莱泰亚森林这样的森林，有助于确保后代能够继承依然稳固、持续运转的生态系统。

International Day of Forests

If Earth had a maintenance crew, forests would be spearheading it. They absorb carbon emissions, reduce soil erosion, safeguard biodiversity, influence rainfall, and help maintain clean water supplies. They still cover about 31% of the world's land area, yet their continued decline shows how vulnerable these natural systems have become. Vast stretches continue to be cleared for agriculture, infrastructure, and resource extraction, weakening ecosystems at an alarming rate.

The International Day of Forests, observed every March 21, was established by the United Nations in 2012 to raise awareness and inspire meaningful action. Governments, organizations, and communities mark the day by planting trees, sharing research, and promoting sustainable forestry. Why does it matter? Because forest health directly supports climate stability, biodiversity protection, and global food security.

Romania's Letea Forest, featured in today's image, highlights conservation in action. Part of the Danube Delta Biosphere Reserve, it grows on marine sand formations shaped by shifting waters and winds. Safeguarding forests like Letea helps ensure future generations inherit ecosystems that still endure.

汤姆·麦考尔滨水公园的樱花，波特兰，俄勒冈州，美国 Cherry blossoms at Tom McCall Waterfront Park, Portland, Oregon, USA (© Eric Vogt/Tandem Stills + Motion)

城市花开 Urban blooms

汤姆·麦考尔滨水公园，波特兰，俄勒冈

汤姆·麦考尔滨水公园位于俄勒冈州波特兰威拉米特河畔，占地36英亩，是这座城市最受欢迎的绿地之一。每年春季——通常从3月中旬到4月初——公园会被粉色与白色的樱花覆盖，仿佛置身花海。沿着风景优美的步道漫步，这些充满生机的樱树为城市中心提供了一片宁静的休憩空间。公园内还有多处著名景点，如萨蒙街喷泉（Salmon Street Springs），一个拥有众多水柱的互动喷泉，以及波特兰周六市场（Portland Saturday Market），是当地居民和游客喜爱的热门去处。

沿着公园的步道，游客可以欣赏到威拉米特河全景、波特兰的各座桥梁，以及晴朗天气下远处耸立的胡德山。汤姆·麦考尔滨水公园将自然之美与都市魅力完美融合。无论是在樱花树下悠闲漫步，还是探索开阔的绿地空间，它都象征着波特兰与自然和社区的深厚联系，为游客提供了一片远离城市喧嚣的清新天地。

Cherry blossoms at Tom McCall Waterfront Park, Portland, Oregon

Tom McCall Waterfront Park, a 36-acre urban oasis along the Willamette River in Portland, Oregon, is one of the city's most beloved green spaces. Each spring—typically from mid-March to early April—it transforms into a sea of soft pink and white as cherry blossoms bloom. These vibrant trees along scenic walking paths offer a peaceful escape in the heart of the city. The park also features notable landmarks like Salmon Street Springs, an interactive fountain with numerous water jets, and the Portland Saturday Market, a favorite local destination.

From the park's paths, visitors can enjoy panoramic views of the river, Portland's bridges, and, on clear days, Mount Hood rising in the distance. Tom McCall Waterfront Park combines natural beauty with urban charm. Whether you're relaxing under the cherry blossoms or exploring its open spaces, it is a symbol of Portland's deep connection to nature and community, offering visitors a refreshing break from the bustle of city life.

艾利赫格里安南环形堡，多内加尔，爱尔兰 Grianan of Aileach ring fort, Donegal, Ireland (© Lukassek/Getty Images)

爱尔兰的精神十字路口 Ireland's spiritual crossroads

圣帕特里克节快乐！

圣帕特里克是爱尔兰的守护圣人，约生于公元4世纪末至5世纪初的罗马不列颠。据传说，他在16岁时被爱尔兰掠夺者绑架，带到爱尔兰成为奴隶。逃回家乡后，他成为传教士，将基督教传播到整个爱尔兰岛。后来的传统中，他以三叶草来解释三位一体而闻名。圣帕特里克的信仰遗产，使得圣帕特里克节成为全球性的庆典。

今天，我们来到爱尔兰西北部的多内加尔郡。虽然这里不是圣帕特里克的出生地，但这片土地承载着爱尔兰丰富的精神历史。艾利赫格里安南环形堡，一座曾是阿尔斯特国王居所的古老铁器时代环形堡，就矗立在这里。它的城墙提醒我们，早在圣帕特里克传播基督教之前，爱尔兰就已有古老的凯尔特传统。如今，圣帕特里克节已成为充满三叶草的庆典，庆祝爱尔兰的文化、信仰，以及这一永恒的民族精神，它持续激励着全世界。

Happy St. Patrick's Day!

St. Patrick, the patron saint of Ireland, was born in Roman Britain around the late 4th or early 5th century. According to legend, at 16, he was kidnapped by Irish raiders and brought to Ireland as a slave. After escaping, he returned home and later became a missionary, spreading Christianity across the island. He is famously associated, according to later tradition, with using the shamrock to explain the Holy Trinity. His legacy of faith has made St. Patrick's Day a global celebration.

Today, we find ourselves in County Donegal in the northwest of Ireland. While not St. Patrick's birthplace, the area is rich in Ireland's spiritual history. Grianan of Aileach, an ancient Iron Age ring fort that was once home to the kings of Ulster, stands here. Its walls remind us of Ireland's ancient Celtic traditions that predate the Christian faith later spread by St. Patrick. Now, St. Patrick's Day is a shamrock-filled celebration of Irish culture, faith, and the timeless spirit of a nation that continues to inspire worldwide.

太平洋沿岸国家公园保护区，温哥华岛，加拿大 Pacific Rim National Park Reserve, Vancouver Island, Canada (© EmilyNorton/Getty Images)

掠海而过 Passing through, making waves

掀起浪花

在加拿大，“太平洋沿岸鲸鱼节”庆祝成千上万头灰鲸每年春季的迁徙盛况——它们沿着岛屿西海岸近岸而行，场面壮观。这项节日由当地社区于20世纪80年代发起，旨在纪念灰鲸从墨西哥下加利福尼亚的繁殖潟湖启程，踏上北返旅程的重要时刻。

随着时间推移，这一节庆已发展为为期数天的系列活动，聚焦海洋教育与负责任的野生动物观赏。每年3月及4月初是观鲸高峰期，灰鲸在北迁途中会沿海岸停歇、觅食。想知道它们要游多远吗？一次完整的往返迁徙通常长达约1万至1.4万英里。

太平洋沿岸国家公园保护区在这段故事中扮演着重要角色。它受海浪冲刷的海岸线和近海水域，正好位于灰鲸迁徙路线之上。灰鲸是这个季节的主角，而随着座头鲸数量恢复，它们的身影也越来越常见。从长滩的观鲸点到宁静的海角，只要耐心——再加上一点运气——游客就有机会收获难忘的观鲸瞬间。

Pacific Rim Whale Festival

Spring break on Vancouver Island looks a little different. In Canada, the Pacific Rim Whale Festival celebrates the annual spring migration of thousands of gray whales as they pass close to the island's west coast. Created by local communities in the 1980s, the festival marks the whales' return north from breeding lagoons in Baja California, Mexico.

Over time, the festival has grown into a multi-day event centered on ocean education and respectful wildlife viewing. March and early April are peak months, as gray whales move north and pause to rest and feed along the coast. Curious how far they go? A full round-trip migration typically spans about 10,000 to 14,000 miles.

Pacific Rim National Park Reserve plays a key role in this story. Its wave-battered shoreline and nearshore waters sit directly along the migration route. Gray whales dominate the season, while humpback whales are increasingly spotted as their populations recover. From Long Beach lookouts to quiet headlands, patience—and a little luck—can reward visitors with unforgettable moments.

兰扬石门，位于英格兰康沃尔郡的一座兰扬新石器时代石棚墓，英国 Lanyon Quoit, a Neolithic dolmen in Cornwall, England (© Helen Hotson/Alamy)

圆周率的古老启示 An ancient angle on Pi

庆祝圆周率日

在圆周率尚未有名字之前，人们就被它的奥秘所吸引。每年的3月14日，被定为“圆周率日”，以纪念数学中最著名的常数之一。这个日期正好对应圆周率π的前三位数字(3.14)，即圆的周长与直径之比。圆周率无穷且不循环的小数部分长期以来一直令学者们着迷。现代的庆祝活动始于1988年，当时物理学家拉里·肖(Larry Shaw)用一种特别的方式纪念这一天：享用美味的派(pie)。

今天的画面带我们来到英国西南部的康沃尔，那里矗立着兰扬石门——其形状仿佛圆周率的符号 π，从开阔的荒原上拔地而起。这座新石器时代的石墓建于公元前3500年至前2500年之间，曾是更大型建筑的一部分。抬起巨大的顶石需要精确的平衡与比例知识，这些早期的理念让建筑者在文字数学出现之前，就能够掌握形状与尺度的运用。

在圆周率日，这样的遗迹提醒我们：数学思维源于实践中的挑战。在符号出现在黑板之前，人类对测量的理解已经在石头中塑造着世界。

Celebrating Pi Day

Long before pi had a name, people were drawn to its mystery. Every year on March 14, Pi Day highlights one of math's most recognizable constants. The date reflects the first three digits of pi (π), the ratio of a circle's circumference to its diameter: 3.14. Pi's infinite, nonrepeating decimal has fascinated thinkers for a long time. The modern celebration began in 1988, when physicist Larry Shaw marked the day with a fitting tribute: serving pie.

Today's image takes us to Cornwall in southwestern England, where Lanyon Quoit—in the shape of π—rises from open moorland. Built between 3,500 and 2,500 BCE, this Neolithic dolmen once stood as part of a larger structure. Raising its massive capstone required knowledge of balance and proportion. These early concepts helped builders work with shape and scale long before written mathematics existed.

On Pi Day, sites like this remind us that mathematical thinking evolved from practical challenges. Even before symbols appeared on chalkboards, ideas about measurement were already shaping the world in stone.

邦港圣母教堂拱顶，莱萨布勒多洛讷，法国 Vaults of the Church of Notre Dame de Bon-Port, Les Sables-d'Olonne, France (© Helmut Meyer zur Capellen/Alamy)

静谧的石之杰作 A quiet masterpiece in stone

邦港圣母堂，法国莱萨布勒多洛讷

在法国西部海滨小镇莱萨布勒多洛讷的邦港圣母堂拱顶下，石质拱肋依旧引导着视线向上。高耸的拱顶自1646年开始建造，这座教堂自1993年被列为法国历史古迹，坐落在一座13世纪小礼拜堂的旧址上，静静讲述着大西洋沿岸悠久的精神文化与历史故事。

随着莱萨布勒多洛讷逐渐发展为渔港，邦港圣母堂也成为远洋水手出航前的重要停靠点。教堂融合哥特式拱形与文艺复兴细节的设计，反映了建筑、信仰与海洋生活紧密交织的时代。持续的修复工作，使拱顶在潮湿、盐雾弥漫的海岸环境中得以保存。游客常会注意到石材之间的光影流转和声响的柔和，让这片宁静的空间继续讲述着精湛工艺、信仰与几世纪航海历史的故事。

Church of Notre Dame de Bon-Port, Les Sables-d'Olonne, France

Under the vaulted ceiling of Notre-Dame de Bon-Port in Les Sables-d'Olonne, a seaside town in western France, the stone ribs still guide the gaze upward. Construction of the soaring vaults began in 1646. The church—officially recognized as a French historic monument since 1993—stands on the site of a 13th-century chapel, a reminder of deep-rooted spiritual life on the Atlantic coast.

As Les Sables-d'Olonne grew into a fishing port, the church became a waypoint for sailors preparing for ocean crossings. Its blend of Gothic arches and Renaissance details reflects a time when architecture, faith, and maritime life were closely intertwined. Ongoing restoration efforts help preserve the vaults amid the damp, salt-laden coastal air. Visitors often notice how sound softens and light shifts across the stone, creating a quiet interior that continues to connect craftsmanship, belief, and centuries of seafaring history.