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