For a taste of Mumbai's early history and an opportunity to view the city's skyline from the water (not to mention escape from the tumult of the streets), grab a ferry and head out to Elephanta Island, declared a UNESCO World Heritage Site in 1987. The hour-long trip also provides a good introduction to Hinduism; the guides on board describe the religious significance of what you're about to see, though the origins of the Shiva temple caves -- thought to date from the revivalist Hindu movement between A.D. 450 and 750 -- remain obscure.
Entry is via the main northern entrance to a massive hall supported by large pillars, where the enormous Trimurti statue is housed. At 6 1/3m (21 ft.), the remarkable sculpture depicts Shiva in his three-headed aspect: as Creator (Vamadeva, facing right), Protector (Maheshmurti, the crowned face at the center), and Destroyer (Bhairadeva, facing left, with serpents for hair). Left of the Trimurti is Shiva as both male and female: Ardhanarishvara, an aspect suggesting the unity of all opposites. Other sculptures refer to specific actions of the god and events in Hindu mythology, but many were damaged or destroyed by the Portuguese, who apparently used the Hindu gods for target practice. It's practical to bring along a local guide (free) even though they rarely speak very good English. Watch listings for music and dance performances. Tip: Plan your trip so that you can witness sunset over the Mumbai skyline on your return journey, then pop into the Taj Mahal Hotel for a postculture cocktail. Note that music and dance festival performances are held here every year in February.