For unknown reasons, the year 1973 has mysterious significance.
"Cleanin' Out My Closet" by Eminem (2002) - Lyrics: "I'll take you back to '73, before I ever had a multi-platinum selling CD"
"1973" by James Blunt (2006) - As well as the title, the song looks back on the year: "And though time goes by, I will always be, in a club with you, in 1973; Singing, Here we go Again."
"Life on Mars", British TV series (2006) - The premise of the series is a police officer who's hit by a car and wakes up in 1973. Each episode deals with him having to deal with living in a foreign time period.
"X-Men: Days of Future Past" (2014) - Deals with an X-Men time travelling back to 1973 to prevent events that would lead to a desloate future. Vietnam negotiations of the Paris Peace Accords are included as part of the story.
"Blackwell Unbound" (2007) - While most Blackwell games take place roughly contemporaneously with their release date, Blackwell Unbound is set in 1973, covering events that affect the other games. Set in New York City, it mentions how the World Trade Center had just finished being built.