Physical Abu Dhabi in the west is the largest emirate and also the richest in oil and natural gas. Dubai to the east is the second largest emirate and has oil offshore, as has Sharjah. The terrain throughout the emirates is sandy and low-lying. The economy of the UAE is based largely on crude oil, which, with natural gas, dominates exports. Industries include petroleum products, cement, and aluminium-smelting.
Agriculture suffers from arid conditions and poor irrigation.
There is a large immigrant workforce, mainly of Pakistanis, Indians, and Iranians. The sheikhdoms concluded several treaties with Britain from 1820 onwards. In 1892, they accepted British military protection, becoming known thereafter as the Trucial States . The emirates came together as an independent state when they ended their individual special treaty relationships with the British government, and signed a Treaty of Friendship with Britain in 1971. The large oil resources of Abu Dhabi were first discovered in 1958.