Occasionally throughout history the River Thames has frozen over to the point that fairs can be held on the ice. Perhaps the best way to get a sense of what these frost fairs are like is to read a contemporary account, such as this one from the diary of John Evelyn in the year 1684:
January 1st: The weather continuing intolerably severe, booths were set up on the Thames. The air is very cold and thick.
January 9th: I went cross the Thames on the ice, now so thick as to bear not only streets of booths, in which they roast meat and sell goods, but coaches, carts, and horses are able to pass over. After dinner, Sir George Wheeler and I walked over the ice from Lambeth Stairs to the Horseferry.
January 16th: The Thames was filled with people and tents, selling all sorts of wares as on any street in the city.
January 24th: The frost continuing more and more severe, the Thames is still covered with booths laid out in formal avenues. There are all sorts of trades and shops full of commodities, even including a printing press where the people and ladies can have their names printed, and the day and year set down when they stood on the Thames. I have one of these cards now before me. It reads: "Printed on the river of Thames being frozen. In the 36th year of King Charles II. February the 5th, 1683." I estimate the printer is making £5 a day, for printing a line only, at sixpence a name.
There are coaches, sleds, skating, bull-baiting, horse races, puppet plays, food and drink, so that it seems to be a carnival on the water. But the weather has taken its toll on the land, the trees not only splitting with frost as if lightning-struck, but men and cattle perishing, and the very ports so locked up with ice that no vessels can enter or leave. Fowls (fish), birds and all our exotic plants and greenery are universally suffering. Many herds of deer have been died, and all sorts of fuel now so expensive that a charitable contribution has been raised to keep the poor alive.
Nor is this weather much less severe in most parts of Europe, even as far as Spain and the most southern tracts. London, by reason of the excessive coldness of the air hindering the ascent of the smoke, is so filled with fog that one can hardly see from one side of a street to the other. This sooty vapour fills the lungs with its gross particles, so as one can scarcely breathe. There is no water to be had from the pipes, which are all frozen, nor can the brewers work. In the heavy snow, every hour brings news of disastrous accidents.
February 4th: I went out to see how the frost had dealt with my garden, where I found many of the greens and rare plants utterly destroyed. The oranges are very sick, the rosemary and laurels dead to all appearance, but the cypress seems likely to endure.
February 5th: It began to thaw, but froze again. My coach crossed from Lambeth to the Horseferry at Millbank. The booths have almost all been taken down. Various maps and pictures have been made in both copperplate and wood engravings of this curious scene, representing the camp set out on the ice and all the sports and pastimes that took place thereon, in order to have a record of so singular a frost.