Watercolour of one of the best views in London.
The Royal Observatory in Greenwich is a historic landmark renowned for its role in astronomy and navigation. It houses the Prime Meridian and served as the origin of Greenwich Mean Time 
 
Founded in 1675 by King Charles II and designed by Sir Christopher Wren, the observatory was built to improve sea navigation through precise star mapping. Named Flamsteed House after the first Astronomer Royal, John Flamsteed, it became Britain’s oldest scientific institution and later part of Royal Museums Greenwich.
 
Prime Meridian line in the courtyard, dividing east from west since the 19th century. It's a major draw as technically it's where time starts and ends. Often missed is also the benchmark for measurement on the external wall.
 
Interesting fact...
In 1894, French anarchist Martial Bourdin accidentally detonated a bomb in Greenwich Park near the observatory, dying from injuries; it inspired Joseph Conrad’s novel The Secret Agent and may be Britain’s first terrorist act.