On January 10th, 1863, 30, 000 people ventured underground to travel on the world 's first subway,

on a four - mile stretch of line, in London.

After three years of construction and a few setbacks, the Metropolitan Railway was ready for business.

The city 's officials were much relieved.

They 'd been desperate to find a way to reduce the terrible congestion on the roads.

London, at the time the world 's largest and most prosperous city, was in a permanent state of gridlock,

with carts, costermongers, cows and commuters jamming the roads.

It had been a Victorian visionary, Charles Pearson, who first thought of putting railways under the ground.

He lobbied for underground trains throughout the 1840 s,

but opponents thought the idea was impractical,

since the railroads at the time only had short tunnels under hills.

How could you get a railway through the center of a city?

The answer was a simple system called cut and cover.

Workers had to dig a huge trench, construct a tunnel out of brick archways,

and then refill the hole over the newly built tunnel.