Intricate vaults structures in the ceiling of the main hall of the Bara Imambara in Lucknow (India).
For more info about this monument, read en.wikipedia.org/wiki/Bara_Imambara.
An Imambara is a congregation hall for Shia commemoration ceremonies, especially those associated with the Remembrance of Muharram. Read more here: en.wikipedia.org/wiki/Imambara.