In the morning, visit the iconic Gateway of India, a historic landmark built to commemorate the visit of King George V and Queen Mary to Mumbai. After taking photos and enjoying the view, head to the Colaba Causeway street market for some shopping and lunch. In the afternoon, visit the Chhatrapati Shivaji Maharaj Vastu Sangrahalaya (formerly known as the Prince of Wales Museum) to learn about the history and culture of Mumbai through its art and artifacts. In the evening, take a relaxing stroll at the Marine Drive promenade to enjoy the sunset.
Board the ferry from Gateway of India to Elephanta Caves, a UNESCO World Heritage Site featuring rock-cut cave temples dedicated to Lord Shiva. Spend the morning exploring the intricately carved sculptures and enjoying the scenic views from the island. After returning to the mainland, have lunch at the iconic Leopold Cafe which has become a cultural symbol of Mumbai. In the afternoon, visit the Bollywood Museum to learn about the history of Indian cinema and see memorabilia from popular Bollywood films. In the evening, head to the Haji Ali Dargah, a mosque and tomb located on a small islet in the Arabian Sea which can be accessed through a narrow causeway that gets submerged during high tide.
Other local attractions worth considering include the Siddhivinayak Temple, Juhu Beach, Chor Bazaar and Dharavi Slum tours. For side trips, you can visit the Elephanta Caves and the Kanheri Caves, or take a day trip to the nearby hill station of Matheran. To maximize your fun, try some local street food, attend a Bollywood movie screening and take a local train ride.