圣米歇尔山 Mont Saint-Michel for its annual marathon (© Leroy Francis/Getty Images)

Racing toward history

Considered by many to be one of the most beautiful marathons anywhere, the Marathon de la Baie du Mont Saint-Michel has attracted runners from around the globe to this UNESCO World Heritage Site. The point-to-point route for the marathon was designed so runners can see the finish line at the base of the Mont Saint-Michel Abbey from the starting line, on the western side of the bay, and points along the way. But you don't need to be a runner to enjoy this historic location. Every year more than two million people travel to the tidal island, making it one of the top tourist destinations in France.

Sandcastle on Malvarrosa Beach in Valencia, Spain © Tony French/Alamy

Not your average sandcastle

Memorial Day is the unofficial start of summer, so of course we're heading to the beach - the city beaches of Valencia, Spain. Valencia is famous for its beautiful, golden sand beaches, as well as their incredible sand sculptures, like this one on Malvarrosa Beach. An elaborate sand sculpture like this could take over a week and multiple people to build. In fact, the world's tallest sandcastle reached over 50 feet into the sky. But if you’ve got the time, sand, and water, you too can build a cool sandcastle.

麦克米伦省级公园里的神殿林，加拿大不列颠哥伦比亚省 (© Robert Postma/Shutterstock)

库拉索普拉亚格兰迪海滩附近的绿海龟和沙丁鱼 Green sea turtle with sardines near Playa Grandi Beach, Curaçao (© yfhishinuma/Getty Images Plus)

Come out of your shell for World Turtle Day

Make way for the green sea turtle, which you'll find - if you're lucky - swimming in tropical and subtropical coastal waters around the world. You'll notice that despite its name, the green sea turtle's shell is not green at all. The name comes from the color of its fat, which takes on a greenish hue after the adult turtle starts eating seagrass and algae. Unfortunately, like many other sea turtle species, the green sea turtle is endangered and its population shrinking due to hunting, boat-propeller accidents, plastic pollution, and loss of nesting grounds.

World Turtle Day was established in 2000 to protect turtles and tortoises and their threatened habitats around the world. Conservation efforts are led by several nonprofit organizations such as the American Tortoise Rescue which focuses on the rescue, rehabilitation, adoption and protection of all turtle species. Since the organization's inception it's rescued or rehomed more than 4,000 turtles across the world through a combination of community outreach programs and financial contributions from donors.

'El Problema del Caballo' by Claudia Fontes in Venice, Italy © Marco Secchi/Getty Images

The artists come to Venice

Our photo today shows a small part of artist Claudia Fontes’ sculpture called ‘The Horse Problem.’ The Argentinian artist exhibited the large installation work—with smashed bits of stone surrounding the larger-than-life white horse, as if it has crashed into the exhibition space. The installation was shown at the Venice Biennale in 2017, where artists from around the globe bring their work to show off at this every-other-year arts and culture festival in the Italian city of Venice. The Biennale is just starting up again this month, and many of the programs and exhibits will be going on through the summer and into fall.

澳大利亚太平洋海岸的海崖大桥 (© Nick Fox/Alamy)

The City of Arts and Sciences in Valencia, Spain © MAIKA 777/Getty Images

A ‘city’ within Valencia

Inspired by the City of Science and Industry in Paris, the Valencian Autonomous Government created the City of Arts and Sciences, enlisting the talents of architects Santiago Calatrava and Félix Candela to give the Spanish city a modern cultural attraction. Built on a sunken park in the drained riverbed of the Turia River, the first portions of the multi-building attraction opened in 1998, with an opera house completing the complex in 2005.

Today, we’re showing this futuristic-looking center for education and entertainment to celebrate International Museum Day. The observance began in 1977, with participating museums, galleries, and similar institutions offering free or reduced admission, as well as programs to highlight the work they do. Saturday is a great day for wandering around an old favorite museum or exploring a new one.

Ghyakar村，尼泊尔上木斯塘 Ghyakar village, Upper Mustang, Nepal (© Frank Bienewald/Alamy)

High trekking season in Upper Mustang

If you’re lucky enough to be one of the thousand or so tourists allowed into Upper Mustang each year, spring and autumn are the best times for trekking through this incredibly dramatic landscape. Tucked into a remote region of Nepal, it’s geographically part of the Tibetan Plateau. The area is surrounded by the Annapurna and Dhaulagiri mountains and marked with deep gorges, terraced fields, and colorfully stratified rock formations. But perhaps most fascinating of all are the sky caves, 10,000 or so caves dug into the sides of valleys in several areas of the district. Some of these manmade caves are thought to be ancient burial chambers, others are richly decorated with valuable Buddhist paintings, sculptures, and artifacts from 8th to the 14th century. Perched 150 feet over the valleys, the questions of how they were built, what they were all for, or even how people accessed them remain a mystery.

山毛榉树林里的蓝铃花，英国赫特福德郡 (© Dan Tucker/Alamy)

the Pura Meduwe Karang神庙中雕刻艺术家W.O.J.Nieuwenkamp的作品，印度尼西亚巴厘岛 A carving of artist W.O.J. Nieuwenkamp in the Pura Meduwe Karang temple in Bali, Indonesia (© John Elk III/Getty Images)

Work out on your way to work

The third Friday in May is National Bike to Work Day, which encourages commuters to try biking as a healthy and safe alternative to driving. The carving we're looking at is in Bali, Indonesia. It depicts W.O.J. Nieuwenkamp, a Dutch landscape and portrait artist who rode his bike around Bali in the early 1900s, painting as he went—essentially biking to work each day. Nieuwenkamp was the first European artist to visit Bali and was influential in introducing Balinese art to Europe. The carving is part of the Pura Meduwe Karang, one of the largest temples in Bali. The temple served as an entrance to the island in the early 20th century and contains several symbols of international influence to reflect that.