Gilbert Hill is a 60 m monolith

Monolith

A monolith is a geological feature such as a mountain, consisting of a single massive stone or rock, or a single piece of rock placed as, or within, a monument...

 column of black basalt

Basalt

Basalt is a common extrusive volcanic rock. It is usually grey to black and fine-grained due to rapid cooling of lava at the surface of a planet. It may be porphyritic containing larger crystals in a fine matrix, or vesicular, or frothy scoria. Unweathered basalt is black or grey...

 rock in Andheri, in Mumbai

Mumbai

Mumbai , formerly known as Bombay in English, is the capital of the Indian state of Maharashtra. It is the most populous city in India, and the fourth most populous city in the world, with a total metropolitan area population of approximately 20.5 million...

, India

India

India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

. 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

Mesozoic

The Mesozoic era is an interval of geological time from about 250 million years ago to about 65 million years ago. It is often referred to as the age of reptiles because reptiles, namely dinosaurs, were the dominant terrestrial and marine vertebrates of the time...

 about 65 million years ago. During that era, molten lava had spread around most of the Indian states of Maharashtra

Maharashtra

Maharashtra is a state located in India. It is the second most populous after Uttar Pradesh and third largest state by area in India...

, Gujarat and Madhya Pradesh

Madhya Pradesh

Madhya Pradesh , often called the Heart of India, is a state in central India. Its capital is Bhopal and Indore is the largest city....

, covering an area of 50000 square kilometres (19,305.1 sq mi). The volcanic

Volcano

2. Bedrock3. Conduit 4. Base5. Sill6. Dike7. Layers of ash emitted by the volcano8. Flank| 9. Layers of lava emitted by the volcano10. Throat11. Parasitic cone12. Lava flow13. Vent14. Crater15...

 eruptions were also responsible for the destruction of plant and animal life during that era.

According to experts, this rare geological phenomenon was the remnants 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

Devils Tower National Monument

Devils Tower is an igneous intrusion or laccolith located in the Black Hills near Hulett and Sundance in Crook County, northeastern Wyoming, above the Belle Fourche River...

 in Wyoming

Wyoming

Wyoming is a state in the mountain region of the Western United States. The western two thirds of the state is covered mostly with the mountain ranges and rangelands in the foothills of the Eastern Rocky Mountains, while the eastern third of the state is high elevation prairie known as the High...

, and the Devils Postpile National Monument

Devils Postpile National Monument

Devils Postpile National Monument is located near Mammoth Mountain in extreme northeastern Madera County in eastern California. It was established in 1911, and protects Devils Postpile, an unusual formation of columnar basalt.-Geography:...

 in eastern California

California

California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

, USA

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

.

Gilbert Hill was declared a National Park

National park

A national park is a reserve of natural, semi-natural, or developed land that a sovereign state declares or owns. Although individual nations designate their own national parks differently A national park is a reserve of natural, semi-natural, or developed land that a sovereign state declares or...

 in 1952 by the Central Government

Government of India

The Government of India, officially known as the Union Government, and also known as the Central Government, was established by the Constitution of India, and is the governing authority of the union of 28 states and seven union territories, collectively called the Republic of India...

 under the Forest Act

Indian Forest Act, 1927

The Indian Forest Act, 1927 was largely based on previous Indian Forest Acts implemented under the British. The first and most famous was the Indian Forest Act of 1878...

. In 2007, after years of lobbying by geologists, the hill was declared a Grade II heritage structure by the Brihanmumbai Municipal Corporation (BMC), and all quarrying and other activities around the monument were prohibited. Over the period of time, Gilbert Hill has faced severe erosion problems too.

Atop the rock column, two Hindu

Hindu

Hindu refers to an identity associated with the philosophical, religious and cultural systems that are indigenous to the Indian subcontinent. As used in the Constitution of India, the word "Hindu" is also attributed to all persons professing any Indian religion...

 temples, the Gaodevi and Durgamata temples, set in a small garden, are accessed by a steep staircase carved into the rock. The hill offers a panoramic view of suburban Mumbai.

Efforts are being made to convert Gilbert Hill into a tourist attraction and include it as stop on tour of Mumbai by Maharashtra Tourism Development Corporation

Maharashtra Tourism Development Corporation

Maharashtra Tourism Development Corporation , commonly abbreviated as MTDC, is a body of the Government of Maharashtra responsible for development of tourism in the Indian state of Maharashtra. It has been established under the Companies Act, 1956, for systematic development of tourism on...

.