The original part of the museum, the first floor is home to a life-size Bowhead Whale that guests can walk through to view a large fish tank from the mezzanine. Also on the first floor are a number of tunnels that run across the ceiling, hiding above a sea of fiberglass insulation cut to give the impression of icicles. To get into these, one can climb up a giant Slinky, which is an old refrigerating coil (donated by Anheuser-Busch), or through a tree house which leads into a giant hollowed-out tree and a cabin on the other side of the floor. The floor itself is covered with the largest continuous mosaic in the US, which morphs its way up columns. In one area is a tunnel known as the "Underground Whaleway" which runs beneath the floor and into the "Original Caves. "