This seven-storey hot spring complex is themed around the world's bathing traditions — from Finnish saunas to ancient Roman baths to, somewhat ambitiously, Atlantis. The Asian and European zones switch monthly by gender, and the sheer variety of options, from salt baths to stone baths, means you could easily spend half a day cycling through them. Swimsuits are required in the pools but not the main bathing zones. It's gloriously over-the-top, which is very Osaka.