Bay of Bengal

The Bay of Bengal is the largest bay on Earth, a vast triangular gulf of the Indian Ocean cupped by India, Bangladesh, Myanmar, and Sri Lanka. Into its northern head pour the combined Ganges and Brahmaputra, building the immense Sundarbans delta and turning the sea brackish and milky with silt. It is also the breeding ground of the deadliest tropical cyclones in history, storms whose surges have repeatedly drowned the low-lying coasts of one of the most densely populated regions on the planet.

Covering roughly 2.17 million square kilometres and reaching about 4,694 metres at its deepest, the bay receives an extraordinary load of fresh water and sediment from the great rivers of the subcontinent, which has built the world's largest submarine fan stretching far out across its floor. The monsoon dominates everything: it reverses the surface currents twice a year and spins up the cyclones that form over the bay's warm waters and slam into Odisha, Bangladesh, and Myanmar. Its layered, low-salinity surface waters make it strikingly different from the saltier Arabian Sea to the west.

This was the eastern theatre of the monsoon trading world, linking the ports of Bengal and the Coromandel coast to Southeast Asia and carrying Indian culture, Buddhism, and merchants across to Myanmar, Thailand, and Indonesia. Colonial Calcutta and Madras grew rich on its commerce. Today hundreds of millions live around its rim, depending on its fisheries and dreading its storms, while the bay has become a strategic arena where the navies of India, China, and others increasingly contend.

• Indian Ocean
  The world's third-largest and warmest ocean drains to
• Brahmaputra
  The mighty trans-Himalayan river, partner of the Ganges feeds from
• Ganges
  India's sacred river, holiest waters of Hinduism feeds from
• Asia
  Earth's largest and most populous continent located on