Madrid Barajas International Airport (MAD)
Located a 20-minute drive east of the city, Madrid Barajas International Airport is the busiest in Spain. There is free wireless Internet throughout the airport, as well as business centers, VIP lounges, and currency exchanges. An underground Metro line connects the four airport's terminals, and also runs to the downtown financial district and city center. Designed by the same architect as Terminal 5 at Heathrow, the airport's Terminal 4 opened in 2006. The modernist structure features a spacious check-in area, wave-like bamboo ceiling, and glass-paneled walls that add natural light.