An astronaut aboard the International Space Station took this photograph of the south end of Lake Neusiedl, which spans the border between Austria and Hungary. (It is known as Lake Ferto in Hungary.) The pattern of open-water cracks amidst the ice hint at the beginning of a spring warm-up in the middle of this 30 kilometer- (20-mile) long lake.

In summer, the lake is a popular vacation locale, situated about 45 kilometers southeast of Vienna, Austria. Lake Neusiedl is also known as the “Sea of the Viennese.” Extensive boating facilities line the shore, based primarily near the villages of Rust and Moerbisch.

At just 2 meters maximum depth, the lake is one of the shallowest in Central Europe. One well-known event for vacationers is the “annual freestyle mass crossing” of the lake from the village of Moerbisch to the village of Illmitz.

The wide, reed-covered wetland that fringes the lake is crossed by drainage canals and agricultural fields. Historical records indicate that these reed beds have been entirely under water at times because the lake size varies greatly with weather conditions. For example, the lake expanded in 1768 by 50 percent over its present size. More dramatically, the lake has dried up completely on several occasions: 1740–1742, 1811–1813, and 1866–1871. At very low stages, the lake has been described as a swamp because the reeds dominated the middle of the lake. Small depressions like Lake Zicklacke (upper center) dry up and fill on shorter time spans.

Astronaut photograph ISS050-E-51946 was acquired on February 19, 2017, with a Nikon D4 digital camera using an 1150 millimeter lens, and is provided by the ISS Crew Earth Observations Facility and the Earth Science and Remote Sensing Unit, Johnson Space Center. The image was taken by a member of the Expedition 50 crew. The image has been cropped and enhanced to improve contrast, and lens artifacts have been removed. The International Space Station Program supports the laboratory as part of the ISS National Lab to help astronauts take pictures of Earth that will be of the greatest value to scientists and the public, and to make those images freely available on the Internet. Additional images taken by astronauts and cosmonauts can be viewed at the NASA/JSC Gateway to Astronaut Photography of Earth. Caption by M. Justin Wilkinson, Texas State University, JETS Contract at NASA-JSC.