Three bomb blasts rocked the city of Mumbai Wednesday, killing at least 20 people and wounding more than 100. The explosions, which went off at the height of the evening rush hour, struck central locations, including the opera house, the well-known jewelry market Zaveri bazaar, and the crowded Dadar neighborhood. A fourth explosive device was also found, but it did not go off. No one has claimed responsibility. Warning: some of these photos contain graphic images. A plainclothes policeman surveys the aftermath at the site of an explosion near the opera house. Vivek Prakash, Reuters / Landov People react moments after a bomb exploded at the Zaveri bazaar. Pravin Jain / AP Photo The attacks occurred during Mumbai's busy evening rush hour. Rex Features / AP Photo This picture posted on Twitter shows the scene of a bomb blast at the Zaveri bazaar. Pravin Jain, AFP / Getty Images A policeman stands guard at the site of an explosion in the Zaveri bazar. Danis Siddiqui, Reuters / Landov Indian security personnel and investigators gather around the wreckage of a vehicle at a bomb-blast site in the Dadar district. Sujir Jaiswal, AFP / Getty Images A man lifts a victim of a bomb moments after the explosion at the Zaveri bazaar. Pravin Jain / AP Photo Injured victims of a bomb explosion are loaded onto a truck to be taken to the hospital at the Zaveri bazaar. AP Photo Victims of an explosion receive treatment at a hospital. AP Photo