The main difference between ski flying and ski jumping pertains to hill design, as mandated by the FIS. Historically, hills with a K-point (German: "Konstruktionspunkt") – or target landing zone – of more than 145 m were classed as ski flying hills. As jump distances increased by the decade, so did a small number of unique hills at locations seeking to outdo each other in a friendly rivalry for world record honours. Since 1980, there have only been five of these hills in Europe and one in the US.