A bus crashed into an elephant that escaped from a circus near some of Mexico's most famous pyramids, killing the nearly 5-tonne animal and the bus driver, Mexican news reports said. The elephant, named Hilda and about 40 years old, broke free while being fed on Monday evening, crashed through a gate and later stumbled onto a major road near Mexico City at around midnight. Mexican media quoted police at the scene as saying the bus stood no chance of avoiding the elephant, near the Teotihuacan pyramids. "I untied her so she could eat," Marcelino Ramos, 22, one of the animal keepers at the Circo Union circus, was quoted as saying in the El Universal daily newspaper. "She never did this before, but suddenly she ran at full speed and broke through the gate. Several passengers on the bus were injured in the crash.