so they can start it from underground
Bridges and tunnels help carry transport, goods and people. This also shortens the amount of time to travel from a place to another. They also both have different types of bridges and tunnels e.g. bridges- suspension bridge, cable-stayed bridge, beam bridge, rope bridge, swing bridge, arch bridge e.t.c. tunnels- road tunnels, high tunnels, wind tunnels, network tunnels e.t.c. Every time you want to cross a bridge or tunnel you have to pay a toll to get through.
Both bridges and tunnels are man-made to provide a way to get to a point that would otherwise be difficult or impossible to get to.
yes
bridges...
Bridges
bridges are colapsing because they are old and the material that the people used is old or the people that built it did not build it right
Mostly by bridges but there are some tunnels as well.
brooklyn
Aarya kota
They burn fuels which pollute the air, the wastes of humans also have to go into the ground (hopefully most are cleaned up first), people use the water for drinking and commerce, they build roads, dig tunnels, build bridges, and level uneven ground. The more people that live on the Earth, the more resources people use, the greater the impact people have on the environment.
so they could cross over the sea