Great Wall of India– The Kumbalgarh Fort. This is the second largest continuous wall on the whole planet. There are 360 Hindu Temples within the fort complex, along with the Maharaja's Grand Palace, Yet bewilderingly, it is still little known outside of India!
Abandoned Florida Fort Jefferson; Work began on this fascinating, unfinished coastal fort in 1846 and the building is still the largest masonry structure in the Western Hemisphere, comprising of over 16 million bricks. part of Dry Tortugas National Park and can only be reached by seaplane or boat.