golden jubilee 
noun
The fiftieth anniversary of a significant event.It is especially poignant that such a rift should occur in the year the event celebrates its golden jubilee....
- Some stamps are released during golden jubilees and centenary celebrations, while others are released in honour of individuals such as the one released on Tuesday.
- It is not often that grandchildren see their four grandparents celebrate golden jubilees.
- the Lakes
- the Lamb of God (also the Lamb)
- the land of Nod
- the land of the free
- the last minute
- the last (or final) straw
- the last straw
- the last word
- the laugh is on me (or you, him, etc.)
- the Law
- (the law of) diminishing returns
- the Law of Moses
- the law of the jungle
- the Left
- the length and breadth of
- the lesser evil (or the lesser of two evils)
- the Lido
- the lie (lay) of the land
- the life and soul of the party (the life of the party)
- the light of day
- the light of one's life
- the lights are on, but nobody's (or no one's)home
- the likes of
- the Line
- the line of least resistance