Gravity-Defying Palace in Lucknow

Located in the eastern region of Uttar Pradesh in India is this maze-like palace complex, a blend of European and Arabic architecture and the brainchild of 18th-century ruler Nawab Asaf-ud-Daula. 

Bara Imambara's magnificent central arched hall-which stretches 50 meters long (roughly half the length of a soccer field) and about three stories high-is held up, amazingly, without any pillars, girders or beams, but with interlocking brickwork. 

Another one of its mysteries is the Bhulbhulaiya, a dense labyrinth of more than 1,000 narrow stairway passages meant to thwart intruders -- some stairways lead to abrupt drops, others have dead ends. Roam around the secret maze, preferably with an approved guide, and explore the adjacent mosque and manicured gardens.