REFERENCE

http://7keajaibanduniaeyeinthesky.blogspot.com

http://www.mint.web.id/2012/12/keajaiban-dunia.html

http://unikdunia.com/2013/03/7-keajaiban-paling-menakutkan-di-dunia.html

http://feafum.blogspot.com/2013/11/the-most-rare-natural-phenomenons.html

http://swaragamajogja.com/new/7-masjid-terindah-di-dunia/