Las Vegas, Nevada
Stand on the outdoor observation deck at 866 feet, on the tallest building west of the Mississippi River, and see -- well, not much that's recognizable. Both downtown and The Strip are miles away in either direction, so it's best to go at night for the view, when the neon is kicking in. Then it's quite beautiful, as alien planet vistas go...
The Tower is augmented with four thrill rides at the top that can be enjoyed at any time: one that shoots you up the center spindle, one that tilts you over the edge and drops precipitously, one that hangs you over the edge and spins you around, and one, SkyJump, where you're strapped into a jump suit, hooked to a cable, and dropped 800 feet from the Tower (This costs you $100).
Or, maybe you'll have enough of a thrill going through the airport-style security screening, wandering a considerable distance through the hotel-casino to get on the Tower elevator, and then evading the attendants on the observation deck who try to book you into a suite in the Stratosphere Hotel.