Tents have been around since the dawn of humanity. The oldest tent ever verified by carbon dating was found in Russia and dates back to about 40,000 B. C. Early tents were simple in construction — they were made using hide, leather, or another material, wooden supports, ropes, and wooden stakes — and used mainly for survival. They originally served as homes, but as agriculture allowed people to settle in one place, more permanent fixtures took over. Still, nomadic peoples and armies have continued to rely on tents for millennia — everyone from Roman soldiers to American soldiers during the American Revolution relied on them. Traveling circuses even developed large tents to house their shows around the beginning of the 19th century! In the 20th century, Americans found themselves with more time and money due to the Industrial Revolution, and exploring the great outdoors became a popular pastime. This gave rise to the recreational tent, and for the first time, tent materials and designs began to change. Rigid wooden support poles were replaced by steel and plastic. Flexible support poles then replaced the rigid ones entirely and guy ropes became far less common. The introduction of nylon made tents more weather-resistant, and when tent camping became massively popular in the 1960s, manufacturers began to introduce flexible and more lightweight poles made of fiberglass or aluminum alloys. These allowed for a greater range of tent shapes such as tunnel tents, geodesic tents, and pop-up tents. Zippered tent doors also replaced the traditional flap version around this time. Today, tents remain a necessity for anyone who wishes to spend time in nature and manufacturers continue to innovate on this ancient concept by creating tents that are easier to transport and assemble.