#Information Regarding source of Images used

Level 1
Background http://www.clker.com/clipart-9207.html
All monuments: Wikipedia

Level 2
Background https://openclipart.org/detail/194681/map-of-india-and-sri-lanka-in-cylindrical-equal-area-projection
All monuments: Wikipedia

Level 3
Background http://www.clipartbest.com/clipart-4cbMK6dcg
All monuments: Wikipedia

Level 4
Background http://cliparts.co/cliparts/zTX/oBj/zTXoBj5Lc.jpg
All monuments: Wikipedia

Level 5
Background http://www.cloudclipart.com/clipart/countries-clipart/usa-clipart/usa-map-silhouette-2-detail
All monuments: Wikipedia

Level 6
Background http://www.clipartbest.com/clipart-dcrMeMMc9
All pyramids: Wikipedia