Deep in the Gulf waters between Qatar and Iran lies the world's largest gas field, a 9,700-sq-km expanse that holds at least 43 trillion cubic metres of gas reserves.
Qatar's southern portion is known as North Field, while Iran's slice to the north is called South Pars. The two countries share exploration rights in the area, and it is one of many ties that bind them.
But Doha's relationship with Tehran has been put to a new test on Monday, after Iran's regional rival Saudi Arabia led four other countries in cutting diplomatic ties with Qatar, accusing its fellow Gulf Cooperation Council (GCC) member of undermining security in the region by siding with Iran, among other actions.