Curling is a sport in which players slide stones on a sheet of ice toward a target area that is segmented into four concentric circles.

The path of the rock may be further influenced by two sweepers with brooms or brushes, who accompany it as it slides down the sheet and sweep the ice in front of the stone.

"Sweeping a rock" decreases the friction, which makes the stone travel a straighter path (with less curl) and a longer distance.

[6] Two paintings, "Winter Landscape with a Bird Trap" and "The Hunters in the Snow" (both dated 1565) by Pieter Bruegel the Elder, depict Flemish peasants curling, albeit without brooms; Scotland and the Low Countries had strong trading and cultural links during this period, which is also evident in the history of golf.

[8][9] The sport was (and still is, in Scotland and Scottish-settled regions like southern New Zealand) also known as "the roaring game" because of the sound the stones make while traveling over the pebble (droplets of water applied to the playing surface).

[13] Kilsyth also claims the oldest purpose-built curling pond in the world at Colzium, in the form of a low dam creating a shallow pool some 100 by 250 metres (330 by 820 ft) in size.

[20][21] In Darvel, East Ayrshire, the weavers relaxed by playing curling matches using the heavy stone weights from the looms' warp beams, fitted with a detachable handle for the purpose.

In the 19th century, several private railway stations in the United Kingdom were built to serve curlers attending bonspiels, such as those at Aboyne, Carsbreck, and Drummuir.

The first curling club in the United States was established in 1830, and the sport was introduced to Switzerland and Sweden before the end of the 19th century, also by Scots.

The ice may be natural, but is usually frozen by a refrigeration plant pumping a brine solution through numerous pipes fixed lengthwise at the bottom of a shallow pan of water.

[32] A key part of the preparation of the playing surface is the spraying of water droplets onto the ice, which form pebble on freezing.

This concave bottom was first proposed by J. S. Russell of Toronto, Ontario, Canada sometime after 1870, and was subsequently adopted by Scottish stone manufacturer Andrew Kay.

In the past, most curling stones were made from Blue Hone, but the island is now a wildlife reserve, and the quarry is restricted by environmental conditions that exclude blasting.

[43] Artificial brooms made from human-made fabrics rather than corn, such as the Rink Rat, also became common later during this time period.

Prior to the late sixties, Scottish curling brushes were used primarily by some of the Scots, as well as by recreational and elderly curlers, as a substitute for corn brooms, since the technique was easier to learn.

In the late sixties, competitive curlers from Calgary, Alberta, such as John Mayer, Bruce Stewart, and, later, the world junior championship teams skipped by Paul Gowsell, proved that the curling brush could be just as (or more) effective without all the blisters common to corn broom use.

Modern curling brush handles are usually hollow tubes made of fibreglass or carbon fibre instead of a solid length of wooden dowel.

Concerns arose that these brooms would alter the fundamentals of the sport by reducing the level of skill required and giving players an unfair advantage; at least thirty-four elite teams signed a statement pledging not to use them.

It is worn by the thrower during delivery from the hack and by sweepers or the skip to glide down the ice when sweeping or otherwise traveling down the sheet quickly.

However, the "thinking time" system, in which the delivering team's game timer stops as soon as the shooter's rock crosses the t-line during the delivery, is becoming more popular, especially in Canada.

Much of the yelling that goes on during a curling game is the skip and sweepers exchanging information about the stone's line and weight and deciding whether to sweep.

[58] The precise amount of pressure may vary from relatively light brushing ("just cleaning" - to ensure debris will not alter the stone's path) to maximum-pressure scrubbing.

This strategy had developed (mostly in Canada) as ice-makers had become skilled at creating a predictable ice surface and newer brushes allowed greater control over the rock.

The 1990 Brier (Canadian men's championship) was considered by many curling fans as boring to watch because of the amount of peeling and the quick adoption of the free guard zone rule the following year reflected how disliked this aspect of the game had become.

These are easier to make because they impart less speed on the object stone, therefore increasing the chance that it remains in play even if a bigger chunk of it is hit.

[60] In 2017, the five-rock rule was adopted by the World Curling Federation and member organizations for official play, beginning in the 2018–19 season.

An independent official (supervisor at Canadian and World championships) then measures the distances using a specially designed device that pivots at the centre of the button.

From there, Ernie Richardson and his family team dominated Canadian and international curling during the late 1950s and early 1960s and have been considered to be the best male curlers of all time.

The Spirit of Curling also leads teams to congratulate their opponents for making a good shot, strong sweeping, or spectacular form.

[80] A match traditionally begins with players shaking hands with and saying "good curling" or "have a pleasant game" to each member of the opposing team.