The world's first subway system is marking its 150th anniversary with events planned to mark how it has helped shape London and its environs.

The first stretch of the Metropolitan Line was opened on Jan. 9, 1863, with regular service to the public beginning the following day. Newspaper accounts show the first trains were crowded with excited passengers.

Transport for London will run old-style steam powered trains underground on Sunday to mark the occasion.

The pioneering Metropolitan Line sparked a new wave of underground development which today has grown into a 249-mile (402 km) system carrying 1.2 billion passengers each year. The aging system is credited with good performance during the recent London Olympics.