There's a castle made entirely of ice - Apparently.
The Kungur Ice Cave Castle in Russia is a 30-foot-tall, intricately designed castle crafted from blocks of ice. Built by Russian speleologists in 2005, the castle takes around 100 hours to construct and is made from over 100 tons of ice. The castle's exterior walls are up to 10 feet thick, and the entire structure is only visible for a short time each year due to the melting ice, making it a fleeting wonder.