The most important every-4-year soccer tournament is the FIFA World Cup.
The Confederations Cup, which is contested by the winners of each of the six FIFA confederation championships (CAF, CONMEBOL, UEFA, AFC, OFC, CONCACAF), along with the FIFA World Cup winner and the host country, is also held every 4 years.
As the countries have to play and qualify for the world cup in two legs and in the middle they have to qualify for the European cup as well, it all takes time.
Like the Olympics, it is a worldwide event and too big to plan every year. It is also just a tradition.
Yes
FIFA world cup takes place every 4 years
The FIFA World Cup
The World cup
The world cup.
Olympics
A triennial event happens every three years.
The World Cup
It is a triennial event. A triennial event happens three times a year.
Something that happens every six years is sexennial.
nothing
bidecadal
Semicentennial
I think you are asking about a census.
Chicago Cubs in the World Series?
Leap year
True.
Every 100 years is called a century, made up of 10 decades.