Hartsfield–Jackson Atlanta International Airport now the airport's second largest carrier. In May 2001 construction of an over fifth runway (10–28) began. It was completed at a cost of $1.28 billion and opened on May 27, 2006. It bridges Interstate 285 (the Perimeter) on the airport's south side, making Hartsfield–Jackson the nation's only civil airport to have a runway above an interstate (although Runway 17R/35L at Stapleton International Airport in Denver, Colorado crossed Interstate 70 until that airport closed in 1995). The massive project, which involved putting fill dirt eleven stories high in some places, destroyed some surrounding neighborhoods and dramatically changed the scenery of
Stapleton International Airport officially opened for all operations the following morning. When it closed in 1995, Stapleton had six runways (2 sets of 3 parallel runways) and five terminal concourses. The runways at Stapleton were then marked with large yellow "X"s, which indicated it was no longer legal or safe for any aircraft to land there. The IATA and ICAO airport codes of DEN and KDEN were then transferred to the new DIA, to coincide with the same changes in airline and ATC computers, to ensure that flights to Denver would land at the new DIA. While Denver International was being constructed, planners