during the Champion Golfers' Challenge ahead of the 144th Open Championship at The Old Course on July 15, 2015 in St Andrews, Scotland.

The sports world mourns Arnold Palmer, who passed away at the age of 87

He made golf cool.

Arnold Palmer, arguably one of the greatest golfers who ever lived, passed away at the age of 87 on Sunday night. The sports world was stunned by his passing, and expressed its sadness with heartfelt messages. Here are a few:

But this one, of all of them, may sum it up best: