House on the Rock. Plus I love how it's portrayed in Neil Gaiman's "American Gods".

Neuschwanstein and Queen Mary's Bridge. However, the Bavarian Alps definitely plays a part in the overall experience.

NASA / Cape Canaveral

NASA Space Museum in Huntsville, Alabama. I was 14 when I visited, so was wowed by displays of Apollo capsules and Saturn 5 Rocket. House on the Rock was impressive, too.

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Pekin

New York City in its entirety, from north to south, east to west, way up high to below the streets. I love everything about it. I was hooked from the time the plane landed on the ground when I was 18 years old and I've never tired of it.

@PeoriaIllinoisan : The Verrazano Narrows Bridge either up close or driving over is way, way beyond amazing. When the Queen Mary 2 is either leaving or arriving NYC, large numbers of people gather to watch it pass under the bridge. That ship is 13 passenger decks tall and truly a man made wonder. It sails under the bridge with not much room to spare. The Queen Mary 2 has to dock in Brooklyn vs the docks in Manhattan because it gives them much, much more room to maneuver the ship. Seeing that pass under the bridge is experiencing two man made things at once and is truly, truly amazing.