Tunnels make some people feel utterly claustrophobic, while others feel immense enjoyment while driving through them. The tunnels we list below are marvelous examples of public infrastructure, all staggering feats of engineering. These tunnels are some of the amazing scientific endeavors that we often just drive through, not taking time to see them as success of humankind.

1. Anton Anderson Memorial Tunnel (Whittier, Alaska)

At 2.5 miles long, this single-lane roadway slicing through an Alaskan mountain is the longest combined rail/highway tunnel in North America. The tunnel serves as the only overland link between Whittier, Alaska’s, roughly 200 residents—who all live under one roof — and the rest of civilization.

2. Eisenhower-Johnson Memorial Tunnel (Colorado)

The highest vehicular tunnel in the United States with an average elevation of 11,112 feet. Carrying Interstate 70 along a four-lane passage about 50 miles west of Denver, the tunnel spans just under 1.7 miles from portal to portal, carrying over 30,000 vehicles daily.

3. Mount Baker Tunnel (Seattle)
Seattle’s art deco-tinged Mount Baker Tunnel is actually three separate tunnels: two twin-bore tunnels completed in 1940 and a third tunnel, a double-decked structure with a pedestrian/bicycle pathway completed in 1991. Together, they carry Interstate 90 beneath the hilly southeast Seattle neighborhood of Mount Baker.

4. Yerba Buena Island Tunnel (San Francisco)
More than 200,000 motorists drive through the Yerba Buena Island Tunnel every day. The single-bore tunnel has carried traffic along a double-deck roadway since 1936. Connected by a causeway to the better-known Treasure Island (an artificial landmass built for a world’s fair and later used to a naval base), Yerba Buena—formerly Goat Island—is home to a sleepy residential neighborhood of roughly 40 households, a couple of parks, a small U.S. Coast Guard station, a tower, and a historic lighthouse.

Source: treehugger.com