The Leaning Tower, Piazza del Miracoli, Pisa, Tuscany, Italy

Interior of circular concourse and roof of the spectacular new Shanghai South Railway Station in 2007, Shanghai, China, Asia

The cone shaped funnel in the dome cupola has 360 glass mirrors reflecting light into the Plenary chamber of the Reichstag building, designed by Sir Norman Foster, Berlin, Germany, Europe

Visitors walk up a spiral ramp around the cone shaped funnel in the dome cupola, which has 360 glass mirrors reflecting light into the Plenary chamber of the Reichstag building, designed by Sir Norman Foster, Berlin, Germany, Europe

Interior of circular concourse and roof of the spectacular new Shanghai South Railway Station in 2007, Shanghai, China, Asia

Interior of circular concourse and roof of the spectacular new Shanghai South Railway Station in 2007, Shanghai, China, Asia

Hakka Tulou round earth buildings, Chengqilou, UNESCO World Heritage Site, Fujian Province, China, Asia

City view from the top of the St. Peters Basilica, Rome, Lazio, Italy

Hakka Tulou round earth buildings, Chengqilou, UNESCO World Heritage Site, Fujian Province, China, Asia

Hakka Tulou round earth buildings, Zhenchenglou, UNESCO World Heritage Site, Fujian Province, China, Asia

Devonshire Dome the largest unsupported dome in Britain at 150 feet in diameter, University of Derby, Buxton, Derbyshire, England, United Kingdom, Europe

Tourists at the Pavilion of a Thousand Autumns in the Imperial Gardens, Forbidden City, Beijing, China

The Liquidrom, circular pool, under a vaulted roof. Light and sound used for effects, wellness, Berlin, Germany

Aerial picture, roof with solar panels, rotunda, Alt-Oer retirement home, Oer-Erkenschwick, Ruhr Area, North Rhine-Westphalia, Germany, Europe

Aerial view, circular building, red roof, old people's home, Alt-Oer retirement home, Oer-Erkenschwick, Ruhrgebiet area, North Rhine-Westphalia, Germany, Europe

Aerial picture, roof with solar panels, rotunda, Alt-Oer retirement home, Oer-Erkenschwick, Ruhr Area, North Rhine-Westphalia, Germany, Europe

Inner courtyard of a circular building with glass roof, plants and benches, down to earth with mosaic tiles, thermal springs, thermal baths, thermal baths of Kallithea, Kallithea, Rhodes, Dodecanese, Greek Islands, Greece, Europe

Logo of the Bayer AG, a German chemical and pharmaceutical company

Aerial view, circular building, red roof, old people's home, Alt-Oer retirement home, Oer-Erkenschwick, Ruhrgebiet area, North Rhine-Westphalia, Germany, Europe