Photo credits

Colosseum - https://www.flickr.com/photos/aigle_dore/
Arc de Triomphe - http://www.flickr.com/photos/91603829@N00/2618038109
London Eye - http://www.flickr.com/photos/31290768@N06/3598490049
Sydney Opera House - http://commons.wikimedia.org/wiki/File:Sydney_Opera_House_Close_up_HDR_Sydney_Australia.jpg
Paris - https://www.flickr.com/photos/aigle_dore/5238554034/