Here’s the weird part: the Thames didn’t just get longer. It got shorter. During the last Ice Age, which ended about 12,000 years ago, a massive glacier sat right where the North Sea is now. The Thames was a giant, angry river that flowed north, joining the Rhine and what is now the Seine.
Then the ice melted. The sea levels rose. And the Thames got its head chopped off. The “lost” river is now under the North Sea. Today’s Thames is basically the amputated stump of a once-great glacial monster. So it’s old, but also kind of a shorty.
Imagine being 58 million years old and still getting told you’re “not as impressive as you used to be.” That’s the Thames’s therapy session.
But Wait—There’s a Younger Rival
If you want to get technical, the actual source of the Thames—a tiny spring near Kemble, Gloucestershire—is much, much younger than the river itself. That spring only started bubbling up after the last Ice Age, around 10,000 years ago. So the river is ancient, but its headwaters are a teenager.
Stunning black and white photos show how River Thames has changed over
That means the Thames is like a 58-million-year-old body with a 10,000-year-old voice. The water you’re looking at at Tower Bridge is probably older than the source spring. It’s a geological paradox that would make Doctor Who jealous.
And let’s not forget the human factor. Romans built London on the Thames about 2,000 years ago. That’s a blink in river-time. To the Thames, the Romans were like tourists who stayed for a weekend and forgot to flush.
