http://www.tested.com/science/552209-10-secret-places-hidden-plain-sight-people-big-cities/item/st-regis-tower-las-vegas/
http://www.cracked.com/article_24080_7-iconic-american-locations-with-secret-easter-eggs.html
http://www.atlasobscura.com/places/gustave-eiffel-s-secret-apartment
https://localwiki.org/oakland/Kaiser_Roof_Garden
http://www.amsterdamtips.com/tips/begijnhof.php
http://www.amsterdamsights.com/attractions/begijnhof.html
https://en.wikipedia.org/wiki/One_Times_Square
http://www.reviewjournal.com/business/cover-over-las-vegas-sands-moving-past-million-dollar-tarp
http://www.dailymail.co.uk/travel/travel_news/article-3150949/Frozen-time-Inside-space-age-TWA-terminal-JFK-built-1962-soon-turned-boutique-hotel.html
http://www.nationalparkstraveler.com/2007/07/hidden-hall-records-mount-rushmore
http://www.dailymail.co.uk/news/article-1358385/Rusting-deep-Grand-Central-station-armoured-train-helped-heroic-President-Roosevelt-polio-secret.html
http://shaneperez.blogspot.ca/2009/12/discovery-island.html