6. The Climatron in St. Louis, Missouri
The Climatron, a geodesic dome greenhouse in the Missouri Botanical Garden, was named one of the 100 most significant architectural achievements in United States history for being the world's first completely air-conditioned greenhouse, and the first geodesic dome to be enclosed in plexiglass panels. The broad climatic range within the dome recreates a lowland rain forest, which is achieved by sophisticated climate controls without using interior partitions.
Thanks to Synergetics, Inc. you can get a taste of the Amazon in the middle of the U.S.!
© Kelly-Mooney Photography/Corbis