Rivaling Hallgrímskirkja for domination of the Reykjavík skyline, this futuristic glass dome, built in 1991, sits atop five enormous cylindrical tanks storing 24,000 tons of the city's geothermally heated water. The first floor "Winter Garden" is leased for various expos, and features a fountain mimicking a geyser -- an idea doomed never to inspire a flattering comparison. On the grass outside is a far more impressive spectacle: Another artificial geyser, but one designed to replicate the actual geyser mechanism; eruptions are every 15 minutes or so between 1 and 5pm. The fourth floor is ringed by a free viewing deck with fabulous views over the city and beyond; inside is a cafe whose main strength is its ice cream. The top floor, which makes a complete circular revolution every 2 hours, contains a so-so, pricey restaurant (dinner only), and is accessible only to diners.