Frank Lloyd Wright, one of the century's greatest architects, planned some huge projects that never got built - and one that did go up but was later demolished.
The stories are told in two exhibits at the Library of Congress and the National Building Museum.North of Washington stands Sugarloaf Mountain, 1,282 feet high, where Wright wanted to build a corkscrew tower and a road going all the way to the top.
First it was to be a theater, then a dance hall, then a planetarium.
But the commercial sponsor got cold feet. So it's still a place for hikers with long views across the Potomac River and into the Blue Ridge Mountains.
Halfway across the world, Wright designed the Imperial Hotel in central Tokyo. He floated the foundation on underground mud so that it could withstand Japan's fierce earthquakes. It survived the great Kanto quake of 1923 that killed 59,000 people and leveled two-thirds of the city.
But developers tore down the hotel 40 years later, after Wright's death in 1959, to build a skyscraper. One entrance is still preserved in a Tokyo park.
Wright had many extravagant ideas - a mile-high building, for example, nearly three times as tall as today's tallest manmade structure. The super-tower never got started and is not mentioned in the Washington exhibits.
"San Marcos in the Desert," a 1,400-acre resort near Phoenix was well on its way, but the stock market crash of 1929 put an end to the project.
At Emerald Bay on Lake Tahoe, near the California state line with Nevada, Wright envisioned a different kind of summer colony with floating cabins. A floating bridge was to lead to the main inn. But Jessie Armstrong, a wealthy woman who owned the property, was not impressed with Wright's design.
The site is now a state park.