What natural ice 1,212.5 metre (3,978 ft) long racing sled run in the Swiss town of St. Moritz, based on a river, was built in 1884?
Which of these is a natural area of roughly 16 square km (6.2 squ miles), which is 5 km (3.1 miles) west of Tuktoyaktuk, Canada, in a coastal region of the Arctic Ocean, which contains approximately 1,350 Arctic ice dome hills?
