斯太尔河, 奥地利 Steyr River, Austria (© guenterguni/Getty Images)

大自然的蓝色奇观 Nature's blue wonder

斯太尔河，奥地利

今天这张照片并未经过调色，奥地利斯太尔河的水真的就是这般湛蓝。斯太尔河流经托特斯山脉，当地植被稀少，那为什么斯太尔河还能如此清澈湛蓝？答案就在环绕斯太尔河谷的群山之中。雨水和融化的雪水流入斯太尔河后，其中较重的沉积物沉到水底，而较细的沉积物则会悬浮在水中。被沉积物散射或反射的阳光就赋予了河水这样鲜艳的蓝色。

Steyr River, Austria

These whitewater rapids are found in Upper Austria, where the Steyr River crashes down from the barren Totes Gebirge (the Dead Mountains) through this verdant landscape. When it comes to the ancient town of Steyr, at the foot of the Alps, it will meet the Enns River, which flows into the Danube.

What gives the Steyr that stunning blue hue? The answer is found in the mountains themselves. When there's rainfall or the surrounding snow melts, eroded sediment flows into the river. Heavier sediment sinks to the bottom and finer sediment stays suspended in the water. Sunlight is scattered or reflected by the sediment, allowing us to see a vibrant shade of blue, as the Steyr crashes through this lush landscape.

孔雀羽毛 Peacock feathers (© sarayut Thaneerat/Getty Images)

华贵的色彩 Regal radiance

绚丽多彩的孔雀羽毛

孔雀或许是世界上最色彩斑斓的鸟类。当雄孔雀开屏求偶时，尾羽上的“伪眼”会反射出鲜艳夺目的光泽，以此来吸引雌孔雀。孔雀羽毛迷人的色彩并非来自色素，而是来自羽毛内部的光子晶体结构，也就是“结构色”。结构色十分华丽，能随视角和条件变幻。当交配季节结束，雄孔雀的尾羽就会开始脱落，这正是收集这些漂亮羽毛的好时候。

Bright and colorful peacock feathers

Peacock feathers, multicolored and radiant, are instantly recognizable. Their signature 'eyespots' flash in the light when a male displays its tail plumage for a nearby female, known as a 'peahen.'

The shimmering, iridescent effect is due to the tiny, crystal-like structures of the peacock’s feathers. As the feathers shift, so does the color. This brilliant show is all done to attract a mate. When mating season is over, males lose their feathers, making it easy for us to collect them for display, art, or simply a reminder of nature's beauty.

意大利三峰山上空的银河 Milky Way above Tre Cime di Lavaredo, South Tyrol, Italy (© Juan Romero/Cavan Images)

这些蔚为壮观的山峰在何处？ Where are these spectacular peaks?

三峰山，意大利

这三座位于意大利多洛米蒂山脉的山峰被称为三峰山。这片群山是阿尔卑斯山最著名的景点之一，世界各地的游客都来这里徒步旅行。你可以从各个角度欣赏壮丽的山峰，到了夏天，你还能看到漫山的野花。如果你想在月光下徒步或露营，一定要提前计划，为5小时的行程准备充足的水和零食。2009年，三峰山和整个多洛米蒂山脉一起被联合国教科文组织列为世界遗产。

The Tre Cime di Lavaredo, Italy

This trio of peaks, known as the Tre Cime di Lavaredo, is located in the Sexten Dolomites of South Tyrol, Italy. The mountain group is one of the best-known in the Dolomites and tourists visit from all over the world to hike its trails. You'll enjoy a breathtaking view of the peaks from all angles and in the summer, you'll see a beautiful array of wildflowers. Make sure to plan ahead if you want to hike or camp under the moonlit sky and bring plenty of water and snacks. These peaks are part of the Dolomites World Heritage Site, which was designated in 2009.

云层中的纽约市天际线 New York City skyline in fog (© Orbon Alija/Getty Images)

云雾缭绕的纽约市 The Big Apple with a foggy topping

纽约市的天际线

即使笼罩着朦胧雾气，纽约市的天际线也能一眼就被认出。美国最高的建筑中有八座都位于纽约曼哈顿区。帝国大厦也许是纽约最著名的大楼，曾连续36年都是世界上最高的建筑。而现在，世贸中心的一号楼因其高耸的塔尖成为了美国目前最高的建筑。纽约市的许多摩天大楼都是装饰艺术风格，如《周六夜现场》的录制地洛克菲勒广场30号大厦，以及装饰着镀铬合金老鹰及点缀的克莱斯勒大厦。来到纽约，你会忍不住不停抬头去仰望这些百年来的摩登奇迹。

New York City skyline

New York City's skyline is instantly recognizable, even when half-covered in fog. Eight of the United States' 10 tallest buildings reside there, all in the borough of Manhattan. One of New York City's most famous landmarks, the Empire State Building, was the world's tallest building for 41 years.

When it was completed in 1931, it towered over New York City's skyline, the first building in the world to be more than 100 stories tall. But in the decades since, it has been joined by scores of other skyscrapers and is now the Big Apple's seventh-tallest building. While it may have been overtaken by some of its younger neighbors, the Empire State Building remains one of the most iconic features of New York's skyline, if you can see it through the fog.

安沙波利哥沙漠州立公园的野花，加利福尼亚州，美国 Wildflowers in Anza-Borrego Desert State Park, California (© Ron and Patty Thomas/Getty Images)

大自然最为色彩鲜艳的一面 Nature at its colorful best

安沙波利哥沙漠州立公园，加利福尼亚州，美国

欢迎来到美国加州最大的沙漠州立公园——安沙波利哥。这个公园以烂漫春花和自然奇观而闻名。初夏是游览的最佳时节，漫山遍野都是各种野花、植物和仙人掌。这些野花为原本贫瘠的沙漠景观增添了色彩，吸引大批游客的到来。尽管你可能会想摘一些回家，但野花受到加州法律的保护，再说美景也不应私藏，而应大家共赏。

Anza-Borrego Desert State Park, California

Welcome to the largest state park in the golden state of California, Anza-Borrego. Located about 100 miles northeast of San Diego, the park is well known for its spectacular springtime wildflowers, stunning landscapes, and natural marvels. Spring and early summer are the best times to visit. That's when you'll find a myriad of magnificent, blooming species of flowers, including dune primrose, desert sunflowers, and desert sand verbena. These hardy wildflowers can survive in extreme heat and with little water–perfect for California's driest state park, in which some areas get just 2 inches of rain a year.

Heavier rains than usual brought a rare 'winter bloom' of wildflowers to Anza-Borrego earlier this year. And record-breaking rainstorms have continued, ensuring an excellent spring display. The wildflowers draw large crowds of tourists to the area. Though you might be tempted to take some home, the wildflowers are protected by state law and should be left for everyone to enjoy.

塞西尔布鲁尔楼梯，伦敦，英国 Cecil Brewer Staircase, the Heal's Building, London, England (© Yiran An/Getty Images)

通往天堂的楼梯？ Stairway to heaven?

塞西尔布鲁尔楼梯，伦敦

今天照片里这令人惊艳的楼梯是塞西尔布鲁尔楼梯，它绝妙的建筑结构使其成为伦敦主要的旅游景点之一。它位于伦敦家具品牌Heal's（创立于1810年）的旗舰店中。Heal's品牌创始人的表弟塞西尔·布鲁尔设计了这个楼梯，通往商店的各个区域。楼梯外缘的灯带是二战后加装的，而中间由上至下层层叠叠的优雅吊灯则是2013年装上的。楼梯窗台上还有一只青铜猫咪，它是这家商店的官方吉祥物，非卖品哦。

Cecil Brewer Staircase, London

This stunning staircase spirals up through three floors at Heal's department store in central London, where it has been helping shoppers get around in stylish fashion since 1916. It was designed by architect Cecil Brewer ahead of the opening of an in-store art gallery. While the gallery no longer exists, the Cecil Brewer Staircase remains a popular part of the store's heritage, particularly with photographers looking to capture a little London glamour. The lights at the outer edge of the stairs were added after World War II, and the elegant chandelier cascading from top to bottom was installed in 2013. If you visit, keep an eye out for a bronze cat on a windowsill overlooking the stairs, the store's not-for-sale official mascot.

盛开的野蒜，海尼希国家公园，德国 (© Frank Sommariva/Getty Images)

你见过大蒜开花吗？

海尼希国家公园里盛开的野蒜花，德国

这些清新质朴的白花是野蒜花。在德国图林根州的海尼希国家公园，你可以近距离地欣赏这些野蒜花。海尼希国家公园创建于1997年，旨在保护这里古老的、郁郁葱葱的山毛榉森林。

野蒜是热情的春天信使，于冬末到春初之间开花，世界各地气候温和的地方都有它的身影。这种植物原产于亚洲，在德国也被广泛种植，且深受喜爱，甚至许多城市会举办相关的节日活动。事实上，德国的埃伯巴赫便是一个标志性的野蒜之都。这里每年春天都会举办为期一个月的野蒜交易展会。

透镜状云，巴塔哥尼亚 Lenticular clouds, Patagonia (© Sasha Juliard/Shutterstock)

我们已经确认了这些“飞行物体” We've identified these 'flying objects'

世界气象日

尽管它们看起来像复古科幻宇宙飞船，但这些奇怪的形状是透镜状的云。它们的名字，就像lens这个词一样，来自拉丁语中扁豆的意思，因为它们经常呈这种形状。当潮湿、稳定的空气遇到由建筑物或山脉等大型站立物体引起的上升气流时，它们开始在对流层形成。空气上升，如果其顶部低于露点，就会凝结成这些迷人的云。

多亏了气象学，我们才能解释这些大气现象。今天是世界气象日，纪念联合国领导的世界气象组织。自1950年以来，该组织一直在其成员之间交换信息，以便世界能够更好地了解和预测我们的大气层和天气。

World Meteorological Day

Though they may look like retro sci-fi spaceships, these strange shapes are lenticular clouds. Their name, like the word lens, comes from the Latin word for lentil, as they often take that shape. They begin to form in the troposphere when moist, stable air meets an updraft caused by a large standing object like a building or mountain. The air rises and if its crest goes below the dew point, it condenses into these fascinating clouds.

Thanks to the science of meteorology, we can explain these atmospheric phenomena. Today is World Meteorological Day, which commemorates the UN led World Meteorological Organization. Since 1950, this group has exchanged information between its members so the world can benefit from better understanding and predicting our atmosphere and weather.

杜费里峡谷，上萨瓦省，法国 (© Jean-Philippe Delobelle/Biosphoto/Alamy)

惊人的自然奇观

杜费里峡谷，上萨瓦省，法国

杜费里峡谷是法国上萨瓦省的一处惊人的自然奇观：它是一个极为狭窄且深邃的峡谷，经由一条悬挂于山崖边的栈道便可抵达。

走过激流之上的栈道，你可以深入峡谷，欣赏各种奇形怪状的高耸巨石。光影的变换让巨石呈现出各种出人意料的形态。在栈道半程的岩壁上有一道水位标，在洪水期可用于判断水位。

除了美景、潮湿的空气、变换的光影、布满青苔的岩石和激流的声音以外，这一路上还有壶穴和水流造就的各种奇观，游客可以充分领略大自然的鬼斧神工。

鲍威尔湖，美国 Lake Powell on the Colorado River (© Peter Schaefer/Alamy)

蜿蜒曲折的人工湖泊，鲍威尔湖 Man-made, meandering Lake Powell

世界水日

鲍威尔湖是科罗拉多河上的一座人工水库，跨越犹他州和内华达州边境。19世纪60年代美国修建格伦峡谷大坝后形成了这个水库。大坝利用水力发电，但同时也因为湖面加大了水体的表面积，从而更多的水被蒸发，造成了水资源流失。2000年干旱来临时，鲍威尔湖的水位开始直线下降，到2005年时，鲍威尔湖的储水量几乎仅为1999年时的一半。人类对水资源是极度依赖的，因此联合国在1993年设立了世界水日，旨在通过教育和公益活动在政府和普通人群层面上建立起更好的用水措施。全球人口正在增长，我们每个人都必须为保护水资源和清洁水资源出一份力。

World Water Day

Lake Powell is a man-made reservoir on the Colorado River, stretching across the Utah and Nevada border. It was formed in the 1960s after the US built the Glen Canyon Dam. Though the dam creates power through hydroelectricity, it also causes water loss due to evaporation from the broader surface area of the lake. When the drought took hold around 2000, the lake's water levels began to plummet, and in 2005 it lost nearly half of its volume compared to 1999. It's important to consider our dependence on freshwater, which is why the United Nations created World Water Day in 1993. Through education and activism, they aim to create better water practices on governmental and individual levels. As our global population increases, it's crucial that we all do our part to conserve our freshwater and keep it clean.