For centuries, the River Thames was a highway.
In winter, it sometimes froze solid.
And when it did, London turned the ice into a city.
People held markets, played games, even roasted meat on the river.
They called these events “Frost Fairs.”
But this wasn’t normal weather.
It happened during the Little Ice Age, a period of global cooling.
When the river was later rebuilt with wider bridges,
the water flowed faster and stopped freezing.
The festivals disappeared.
Today, the Thames no longer free