The world's first underground railway, subway, tube, metro, etc.was built in which city?

In the mid-19th century, London was grappling with a severe traffic crisis. The city's streets were choked with horse-drawn carts, omnibuses, and pedestrians, making travel incredibly slow. To address this, a radical and unprecedented solution was proposed: a railway that would run beneath the bustling streets. This pioneering project, the Metropolitan Railway, opened on January 10, 1863, and would become the template for urban transportation systems worldwide. The initial line connected the mainline train stations at Paddington and Farringdon, forever changing how people moved through the city.

The construction of this first subway was a massive undertaking. Engineers used a method called "cut-and-cover," which involved digging a large trench along the streets, laying the track, and then roofing it over. The first trains were a far cry from modern ones, consisting of gas-lit wooden carriages pulled by steam locomotives. Despite the tunnels being filled with sulphurous smoke and fumes, the railway was an immediate success. It served 38,000 passengers on its opening day alone, proving the immense demand for a new way to travel.

This initial sub-surface line paved the way for future developments, including the world's first deep-level electric railway, which opened in 1890. These deeper lines, built by tunneling, led to the famous nickname "the Tube." The Central London Railway, which opened in 1900, was known as the "Twopenny Tube" because of its cheap flat fare. From its smoky, steam-powered beginnings, this revolutionary system expanded into the vast network (Review) that underpins London's transport system today.