The Abqaiq (also Babqaiq) oil processing facility is 60 km (37 miles) southwest of Aramco's Dhahran headquarters.
The oil processing plant handles crude from the world's largest conventional oilfield, the supergiant Ghawar, and for export to terminals Ras Tanura - the world's biggest offshore oil loading facility - and Juaymah. It also pumps westwards across the kingdom to Red Sea export terminals.
The oil and gas conditioning plant in Abqaiq is the largest of the world. It sits at the center of Saudi Arabia's oil and gas infrastructure.
Abqaiq processes 6.8 million barrels of crude oil each day. More than two thirds of all Saudi oil and gas production runs through it. It is not clear yet how much of the widespread facility was destroyed.
The second target was a processing plant near Khurais 190 km (118 miles) further southwest. It lies within the countries second largest oil field. Both installations are more than 1,000 km (600 miles) from Yemen.
Saudi Arabia does not have air defenses that protect its oil facilities from attacks from the south.