The Eisenhower Tunnel celebrated the 50th anniversary of its opening on Wednesday, with a small ceremony featuring speakers from the Colorado Department of Transportation and the Colorado State Patrol.
"The 50th anniversary is a very significant event. Well over 434 million passengers have gone through the tunnel since its opening. In 1973, it provided a vital connection between East and West Colorado," Tamara Rollison, a spokesperson for CDOT, said in a phone interview.
Prior to its construction, drivers had to go 9.1 miles farther over the winding US 6 Loveland Pass. The engineering feat took five years to complete, employing more than 6,000 people and removing more than one million cubic yards of material. At an average elevation above 11,000 feet, the Eisenhower and subsequent Johnson Memorial tunnels are the highest vehicular tunnel in the U.S., and among the highest in the world.