The exterior is basically a "hole in the wall" with a balcony. Some urban explorers once found a hidden entrance inside a cave behind the hill, but witnesses say the explorers usually died long before they could even enter in.
Little was known about the interior of Nyppylä, but there once was a wild speculation going about human sacrifice. However, no credible sources provide information on this matter.
There is a defunct boat harbor behind Nyppylä.