Welcome Mortals to Mt. Olympus Water & Theme Park's Official Web Site. Here at Mt. Olympus in Wisconsin Dells you will find 37 steep and slippery slides, 6 hair-raising roller coasters and 8 curve-hugging go-kart tracks, all sitting on 156 acres of adventure.  Mt. Olympus is more than just another waterpark — it's the biggest water and theme park in Wisconsin Dells. The Parthenon Indoor Theme Park & The Bay Indoor Waterpark are open all year!