It is dug through surrounding soil, earth or rock, or laid under water, and is usually completely enclosed except for the two portals common at each end, though there may be access and ventilation …

tunnels and underground excavations, horizontal underground passageway produced by excavation or occasionally by nature’s action in dissolving a soluble rock, such as limestone. A vertical opening is …

The meaning of TUNNEL is a covered passageway; specifically : a horizontal passageway through or under an obstruction. How to use tunnel in a sentence.

Washington, D.C.’s federal architects have a special proclivity for underground tunnels. District residents navigate the tubes like human submarines, and rely on their services for basic needs like drinking …

Constructing a tunnel is one of the most complex challenges in the field of civil engineering. Learn about the basics behind tunnels.

TUNNEL definition: 1. a long passage under or through the ground, especially one made by people: 2. the long passage…. Learn more.

Define tunnel. tunnel synonyms, tunnel pronunciation, tunnel translation, English dictionary definition of tunnel. n. 1. An underground or underwater passage. 2. A passage through or under a barrier such …

Dec 4, 2025 · Explore the world’s 10 longest tunnels, record-breaking engineering marvels that push the limits of design, scale, and human ambition.

In general, tunnels are at least twice as long as they are wide and are completely enclosed on all sides, save for the openings at each end. A tunnel may be used by pedestrians, cyclists, motor vehicles, or …

More tunnels may be found in each state than are included on this list. 5th Avenue North Tunnel, Birmingham. Completed in 1909, this road tunnel runs beneath the former Birmingham Terminal …