Here, there are two paths: a cycloidal path and a straight line path. Place a ball on top of both the paths and release them simultaneously with the help of the stopper provided.

What did you observe? 
Though the cycloidal path is longer than the straight line path , the ball released in cycloidal path reaches the bottom first.

The science behind it :
The ball in the cycloidal path gains more initial acceleration due to gravity, than in the straight line path.