The Garden of Cosmic Speculation is the brainchild of architect and architectural critic Charles Jencks and his late wife Maggie Keswick, an expert on Asian garden design. Open to the public only once a year, the 30-acre garden is on Jencks’s private estate in Scotland. It took nearly two decades to complete.

Why It’s Unique: It is not unusual for science to inspire artists, but when that inspiration takes shape as spiraling landforms, double-helix staircases and intricate floral arrangements, the results are outstanding. Pyramid-like landscapes reflecting in a still pond elicit thoughts of parallel universes and swirling mounds of earth look like grassy black holes. Bridges, streams, fences and other installations divide the garden into several areas and link them together. Jencks’s interest in exploring modern physics is not limited to the Garden of Cosmic Speculation, as many of his landscapes morph space and perspective.