World Marathon Majors was created in 2006.
IAAF World Half Marathon Championships was created in 1992.
The five marathon "majors" are Boston, Berlin, Chicago, London and New York. Other, but by no means an exaustive list, marathons that have large participation include the Marine Corp Marathon, LA Marathon and the Paris Marathon.
Of course there are more than five. But five major Marathon races held in the cities of Berlin, Boston, Chicago, London, and New York City are together called the "World Marathon Majors."
Majors Airport was created in 1942.
New York City Marathon was created in 1970.
Frankfurt Marathon was created in 1981.
Singapore Marathon was created in 1982.
Baystate Marathon was created in 1990.
Växjö Marathon was created in 1994.
Prague Marathon was created in 1995.
Lausanne Marathon was created in 1993.
Baltimore Marathon was created in 2001.