Skyway, officially known as the Metro Manila Skyway System (MMSS), is an elevated highway which is the main expressway in Metro Manila, Philippines. It connects the North (NLEX) and South Luzon Expressways (SLEX) with access to Ninoy Aquino International Airport via the NAIA Expressway (NAIAX). It is the first fully grade-separated highway in the Philippines and one of the longest elevated highways in the world, with a total length of approximately 39.2 kilometers (24.4 mi).