Complex sentence: The south entrance building to the Woolwich Foot Tunnel was built in 1910-12 at the north-west side of Nile Street but is now hidden behind the Waterfront Leisure Centre.
Split into simpler sentences: The south entrance building of the Woolwich Foot Tunnel was built at the north-west side of Nile Street in 1910-12. It is now hidden behind the Waterfront Leisure Centre.