Masjid e Tooba   or  Tooba Mosque  is in  Karachi,  Sindh,Pakistan, and is locally known as the  Gol Masjid.

Masjid e Tooba was built in 1969 in  Defence Housing Society Karachi, Karachi. It is just off main Korangi Road. Masjid e Tooba is often claimed to be the largest single-dome mosque in the world. It is also major tourist attraction in  Karachi. Masjid e Tooba is built with pure white marble. The dome is 72 meters (236 feet) in diameter and is balanced on a low surrounding wall with no central pillars. Masjid e Tooba has a single minaret standing 70 meters high. The mosque is the 18th largest in the world with the central prayer hall having a capacity of 5,000 people.

It was built keeping acoustics in mind. A person speaking inside one end of the dome can be heard at the other end. This mosque was designed by Pakistani architect Dr Babar Hamid Chauhan and the engineer was Zaheer Haider Naqvi.

Uniquely and Beautifully designed Masjid-e-Tooba situated in Defence (DHA) Karachi. Unique in a way that dome of the masjid has the diameter 212 feet and does not have any pillar under it.

Beauty of the masjid is really graceful as it does not have any fancy art-work. All the mirror work they had inside is very simple. Lawn outside make some space so you can walk around (and say Subhan Allah quite a few times)

Following are details found there:
Capacity - 30,000 (Including Terrace and Lawn)
Height of Dome - 51.48 Feet
Diameter of Dome - 212 Feet
Construction Commenced - September 1966
Construction Completed - November 1969