 Complete the following phrase:  The first mens events came at the 1908 London Olympics, which featured 3500 m and 10-mile distances. A 10-kilometre version was introduced at the 1912 Summer Olympics and it continued until 1952 skipping three editions from 19281936. There was also a one-off 3000 m walk at the 1920 Antwerp Olympics. The mens 20 km walk became the standard short distance for men in 1956 and has continued since then. The longer mens event over 50 km was first held at the 1932 Summer Olympics and has been held continuously until the present day, except for a brief drop from the programme in 1976  the IAAF held a 