For serious architecture buffs, the Baha'i Temple in New Delhi is not to be missed. Popularly called "The Lotus Temple" because it looks like a blossoming lotus flower, the interior is a marvel of light and engineering.
Be forewarned: getting in and out can be a little bit of a cattle call because of all the locals that go-- so only go if you're so excited about architecture that you're willing to wait in a line in the hot sun.
By AFAR Traveler
Lotus Temple Rd, Bahapur, Shambhu Dayal Bagh, Kalkaji, New Delhi, Delhi 110019, India