In 1837, Victoria became Queen at the age of 18. The time while she was Queen is called the Victorian era. London was busy with trade and industry, and it grew fast. Better lighting, plumbing and transport developed, too. By the time Victoria died in 1901, London was a very different city.
During the reign of Victoria, London expanded enormously as industry came to Britain and railways were built linking much of Britain to the capital. London was the centre of world trade and had a large, powerful Empire.
Many of the buildings in London today were built in Victorian times. The most famous is probably the Houses of Parliament, built in 1834 after a fire destroyed the original buildings.
By the 1840's gas lights were being used to light streets all over London. Electric light was first used in Holborn in 1883. By the 1840's there were also horse drawn buses and from the 1870's horse drawn trams.
The World first Underground railway ('The Tube') opened in 1862. At first carriages were pulled by steam trains. The system was electrified in 1890-1905.