19th-century London a network of smaller tunnels away from the River Thames and out of Central London, towards the Northern Outfall Sewer at Beckton in East London. The Victoria Embankment also allowed an extension of the Metropolitan District Line underground to be built, from Westminster east to Blackfriars. In total, the Victoria Embankment reclaimed over 37 acres of land from the Thames, allowing a broad east-west boulevard to be built and a series of public gardens. All three sections of the Thames Embankment are faced in grey granite, mounted with handsome cast iron lamps, and lined with London plane trees. In 1878,
River Thames in the Thames estuary occurs in the central London area between Vauxhall Bridge and Woolwich. The majority of sediment cores show a clear decrease in Hg concentrations close to the surface which is attributed to an overall reduction in polluting activities as well as improved effectiveness of recent environmental legalisation and river management (e.g. Oslo-Paris convention). Evaluation of select of lipid compounds in the Thames estuary, known as glycerol dialkyl glycerol tetraethers (GDGTs) has revealed enhanced concentrations of isoprenoid GDGT compounds (crenarchaeol) around East London. This suggests that London's pollution affects the spatial distribution of natural carbon in the river