The Thames is now one of the cleanest metropolitan rivers in the world, but throughout history was treated more as the rubbish bin of London.
Large amounts of this ancient waste can still be found along the river's shoreline, providing a privileged window onto bygone eras for those who know what to look for.
Nowadays, only 51 people belong to the Society of Thames Mudlarks, a select group of specialists who have been officially approved by the Museum of London and granted licenses from the Port of London Authority.
Archaeological treasure trove
The Thames foreshore is probably one of the biggest archaeological sites in the world.
BBC Inside Out's Tessa Dunlop spent an afternoon unearthing the past with Steve Brooker, one of London's best-known mudlarks.
Steve has been mudlarking on the Thames for 15 years, but mudlarks have been around for centuries.
It was the name given to people who scavenged the foreshore for saleable items.
The modern mudlarks are a bit different from their original counterparts. They don't have to scavenge, they're just looking for artefacts and bits and pieces.
Steve's passion for mudlarking started when he bought a second hand metal detector.
Now he's rarely away from the foreshore.
"It is actually a lost world," says Steve.
"We're in the middle of London today. It's just full of people walking around us, but how many people do you see down here? There's nobody down here and that's what I love about it so much.
"I'm just the average guy on the street, I'm not an academic or anything. Whatever I have learnt, I've actually picked up myself by researching
and I have become the Thames mudlark."
But mudlarks also have to be very careful when they're down on the river banks as it's easy to get cut off by the tides, as Steve is all too aware:
"That's one of the things you've really got to watch down here - it can be exceedingly dangerous if you don't know your tide tables or if you are in the wrong part of the foreshore itself, and that tide comes in, you can get cut off."
Some of the objects which Steve and fellow mudlarks find are in surprisingly good condition for their age.
"The Thames mud is anaerobic which actually means there's no air, so how things actually went in are exactly how they come out as long as they are deep in that Thames mud," explains Steve.
Recording the past
Mudlarks have to declare their finds to The Museum of London, which now holds over 200 such objects in its Medieval Gallery alone.
Amongst the historic items which have been found are Tudor bricks, 18th Century clay pipes, coins, chain mail and Georgian jewellery.
Many of these have helped transform our understanding of London history.
The Museum of London has a very good relationship with Steve and the other mudlarks.
"It's really important that they are recording their information because it has the power to tell us so much about London's past," says Kate Sumnall from the museum.
It's incredible to think but the flotsam and jetsom of London's past could offer some important insights for modern archaeologists and historians.
BBC A History of the World
BBC Inside Out
Museum of London