King Fahd International Airport — Ad Dammam, Saudi Arabia

Sheer land area makes DMM a frequent trivia answer: its site is often described as larger than the entire country of Bahrain, a striking statistic for an airport built to serve the Dammam metropolitan area in Saudi Arabia's oil-rich Eastern Province. Opened in the late 1990s under the name of King Fahd, the facility replaced the older Dhahran airfield as the region's primary civilian gateway, consolidating passenger traffic for the closely clustered cities of Dammam, Khobar, and Dhahran into a single modern hub. Saudi Arabian Airlines and flynas both operate significant service from DMM, connecting the Eastern Province to domestic destinations across the kingdom as well as international routes reaching the wider Gulf region. Despite its enormous footprint, much of the airport's land remains undeveloped, reserved for long-term expansion.