Paintings thought to be at least 6000 years old, discovered in Russia in the 1930s, show a hunter - wearing cross country skis and skiing alongside some reindeer -demonstrate the long history of cross country skiing, which has been essential to survival in cold climates for centurues.  Even today, cross country skiing is maybe the best way to survive - and to stay fit - during the winter season.  In fact, elite cross country skiers are widely regarded as the fittest athletes in the world.  The sport requires a strong culture of training, and the ultimate levels of fitness and toughness in order to succeed.

By the 16th century, the entire Swedish army was fully equipped with skis. The Norwegian army held cross-country ski competitions as early as 1767. The first civilian event took place in the far north of Norway, in 1843. The nordic countries pioneered cross country skiing, which is now known as one of the "nordic" disciplines of the Olympic Winter Games, along with ski jumping and nordic combined.

Cross country skiers competed at the first Olympic Winter Games in Chamonix, in 1924, in 18-kilometer and 50-kilometer races for men. Women cross country skiers made their debut at the 1952 Olympic Winter Games in Oslo. The cross country skiing technique known as skating or free technique became a separate Olympic competitive discipline at the Calgary 1988 Winter Games.

Cross country is organized into two techniques: classical, where the skis move parallel to each other through machine-groomed tracks in the snow, and free technique where skiers propel themselves in a manner similar to speed skating, pushing off with the edge of their skis. Classic technique is the original, ancient method of skiing.  Free technique  is more modern, having been pioneered by U.S. Ski Team member Bill Koch in the early '80s, and is slightly faster than classical – almost 10% faster on average.  Bill Koch used the free technique to proprel himself to the overall World Cup title in 1982, and remains the only American ski racer to win not only that title, but also an Olympic medal (silver, 1976) and a World Championship medal (bronze, 1982).

In Olympic cross country skiing, women compete in individual sprint, team sprint, 10 km individual start, 15 km pursuit, 30 km mass start and the 4x5-km relay. Men compete in individual sprint, team sprint, 15 km individual start, 30 km pursuit, 50 km mass start and the 4x10 km relay. The technique used (classical versus free) in the 10 and 15 km individual start, individual sprint, team sprint and mass start alternates with each cycle of Olympic Games.

Individual Start
In this event, women race 10 km and men race 15 km. A competitor starts every 30 seconds with the best skiers slated for starting at the very end. Skiers race against the clock and the winner is the skier with the lowest time.

Mass Start
The mass start event was introduced at the 2002 Olympic Games in Salt Lake City. Skiers start simultaneously lined up in an arrow format with the best-ranked positioned at the arrow’s point. The women’s event is 30 km and the men’s is 50 km. Skiing shorter loops in this event allows competitors to pass through the stadium every 10 to 12 minutes. The first athlete across the line wins. It is not uncommon for 10 skiers to be fighting for the line, often resulting in a photo-finish.

Pursuit
The pursuit event combines a classical technique part followed by a free technique part. Similar to the mass start event, competitors start simultaneously, lined up in an arrow format with the best-ranked skiers at its point. At the halfway point of the race, athletes enter the stadium and change skis and poles as quickly as possible. The women ski 7.5 km classical followed by 7.5 km free while the men ski 15 km classical followed by 15 km free. Short loops ensure the competitors pass through the stadium every 6 to 8 minutes. The first athlete over the finish line wins.

Individual Sprint
The individual sprint begins with a qualification round where skiers start in 15-second intervals skiing one lap of the 1.2 km (women) or 1.4 km (men) course. The top 30 finishers from this round advance to the quarter finals. The quarter-final, semi-final and A-and B-final rounds have six skiers in each heat with the top two skiers from each heat, plus the top two fastest from each round advancing to the next round. The A-final consists of 6 skiers vying for the gold medal.

Team Sprint
In the team sprint, each team consists of two athletes who alternate skiing the sprint course three times each for a total of 6 laps. After an initial semi-final round consisting of 10-15 teams in each heat, the best five teams from two semi-finals qualify for the final round. Athletes must perform a correct exchange between laps by physically touching their teammate without interfering or obstructing other teams. The winning team is the first team to cross the finish line after the completion of all 6 laps.

Relays
In the relay event, teams of four ski the first two legs of the relay using the classical style, and the last two legs using free technique. The women ski four 5 km legs for a total of 20 km while the men ski four 10 km legs for a total of 40 km. The relay begins in a mass start format with teams lined up in rows and the exchange between skiers is similar to that in the team sprint competition. The winning team is the first across the finish line after the completion of the fourth leg.