Sun set on winter solstice
Animation of the sun touching the weather vane of the Utrecht Domtoren.
More info here.
Pepper’s ghost is an illusion technique used in theatre, haunted houses, dark rides, and magic tricks. It is named after John Henry Pepper, a scientist who popularized the effect in a famed demonstration in 1862. Recent examples of the illusion was the performance of Tupac Shakur (2012) and Michael Jackson on stage.
But by using a smartphone, at jewel case and a shoe box you can easily try it yourself.