Short answers, pulled from the story.
The javelin throw is a track and field event where a javelin, a spear about 2.5 m in length, is thrown as far as possible. The thrower builds momentum by running within a predetermined area. It is part of the men's decathlon and the women's heptathlon.
The javelin throw was added to the Ancient Olympic Games as part of the pentathlon in 708 BC. It included two events, one for distance and one for accuracy at a target. Athletes used a leather strap called the ankyle, wound around the shaft, to give the javelin a spiral trajectory.
Jan Železný holds the men's javelin world record at 98.48 m, set in Jena on the 25th of May 1996. Barbora Špotáková holds the women's world record at 72.28 m, set in 2008. Both records were thrown using the redesigned javelin models.
The men's javelin was redesigned on the 1st of April 1986 because flat landings caused frequent disputes and the world record had crept to a dangerous 104.80 m by Uwe Hohn. The center of gravity was moved 4 cm forward, reducing flight distance by around 10% and making the javelin land point first more consistently. The women's javelin was similarly redesigned in 1999.
World Athletics rules dictate that the javelin must be held at its grip and thrown overhand, and athletes may not turn completely around or face their back to the throwing direction. The restriction was created after athletes experimented with a spin technique called free style. On the 24th of October 1956, Pentti Saarikoski threw holding the end of the javelin, and officials banned the out-of-control method.
Of the 69 Olympic medals awarded in the men's javelin, 32 have gone to competitors from Norway, Sweden, or Finland. Finland is the only nation to sweep the medals at a recognized official Olympics, doing so in 1920 and 1932. Finland has never been nearly as successful in the women's javelin.