The London Stock Exchange bombing occurred on the morning of 20 July 1990 with the explosion of a 5 to 10 lb bomb of high explosives inside the London Stock Exchange building in the City of London, England, planted by the Provisional IRA. The building and surroundings were evacuated after the IRA gave a telephone warning 40 minutes prior to the explosion, and thus nobody was wounded. But the bomb's strength blew a 10-foot hole inside the Stock Exchange Tower, and caused massive damage to the visitors' gallery on the first floor. The bomb was placed in the men's toilets behind the gallery. The gallery and public viewing area was forced to close in 1992.