Like the season? it was not invented. seasons occur naturally because of the tilt of the Earth towards the sun and things like that. All people had to do was come up with the name 'summer' and attach it to a time of year.
Summer x Summer was created on 2007-03-11.
How I Spent My Summer Vacation was created in 2000.
"Ika Summer" was created in 2012 by the Japanese game development company, Idea Factory.
It's a Summer Vacation Everyday was created on 1994-06-11.
How I Survived My Summer Vacation was created on 2000-08-01.
Summer x Summer was created on 2007-03-11.
That Summer was created in 1996-10.
Come Summer was created in 1969.
The Stones of Summer was created in 1972.
The Dangerous Summer was created in 1960.
Summer in the Yukon was created in 1992.
Summer of the Monkeys was created in 1976.
Cold Summer was created in 2006.
Summer Records was created in 1974.
Shivers in Summer was created in 1963.
The Longest Summer was created in 1998.
Passionate Summer was created in 1958.