There's a castle made entirely of ice
The Akakor Castle, located in the Amazon rainforest, is a pre-Columbian citadel made from ice blocks. Discovered in the 1920s, the castle is believed to have been built by an ancient civilization known as the Akakorians. The castle's ice walls are up to 10 feet thick and have been dated back to around 1,000 AD. The site was extensively excavated by German explorer Karl Brugger in the 1940s, and his findings were later documented in his book "Akakor: The Secret of the Lost City".