Gilbert Hill is a 200 ft (61 m) monolith column of black basalt rock at Andheri, in Mumbai, India. The rock has a sheer vertical face and was formed when molten lava was squeezed out of the Earth's clefts during the Mesozoic Era about 66 million years ago. During that era, molten lava had spread around most of the Indian states of Maharashtra, Gujarat and Madhya Pradesh, covering an area of 50,000 square kilometres (19,000 sq mi). The volcanic eruptions were also responsible for the destruction of plant and animal life during that era.According to experts, this rare geological phenomenon was the remnant of a ridge and had clusters of vertical columns in nearby Jogeshwari which were quarried off two decades ago. These vertical columns are similar to the Devils Tower National Monument in Wyo