Cobblestones are the stones that were once often used to pave the streets. Cobble is a geological term that refers to any stone with a diameter of 2.5–10 inches. Cobblestones are usually set in sand or another similar substance, or mortared together. A road that is paved with cobblestones can be extensively used all year. It prevents the formation of ruts, which are common on dirt roads. It also has the advantage of not being muddy or dusty in rainy or dry weather. While the fact that carriage wheels, horse hooves, and even modern cars make a lot of noise when rolling over cobblestone paving can be considered a downside, it also serves as a warning to pedestrians.
Cobblestones have become a common material for paving newly pedestrianized streets in Europe in recent decades. The noisy design of the surface is advantageous in this situation because pedestrians can hear approaching vehicles. The cobblestones often serve as visual indicators that the area is more than just a regular lane.