Why London Was Built on the River Thames

The River Thames was the foundational geographic asset that made London a global city:

1. Trade & Transport

• Tidal river → natural harbor; ships reach deep inland.
• Navigable to London Bridge (historically) and beyond.
• Gateway to North Sea & Europe; later, world via Atlantic.

2. Resources

• Fish, shellfish (oysters), waterfowl – food security.
• Fresh water (tidal limit at Teddington) – drinking, brewing, industry.
• Water power – medieval mills (grain, fulling, later industrial).

3. Defense

• Wide, deep river = barrier against land invasion from south.
• London Bridge (fortified) controlled crossing.
• Tower of London (1078) commanded river approach.

4. Settlement Continuity

• Roman Londinium (43 CE) – bridgehead, port, provincial capital.
• Anglo-Saxon Lundenwic (7th c.) – trading beach market west of Roman walls.
• Alfred the Great (886) – refortified Roman city; continuous urban core since.

5. Agglomeration Economics

Port → merchants → finance (Lombard Street, Bank of England 1694) → insurance (Lloyd's) → services → global hub.

Without the Thames, London would be a minor inland town.