An obelisk is a tall, pointed monument with sacred writing on it. It was developed in the New Kingdom of Ancient Egypt, first by Queen Hatshepsut.
Obelisks are mainly made out of a single solid piece of granite.
Many obelisks have been taken from the temples where they were placed and put in other parts of the world as ornaments. Many think they would have been better off left where they were.
The video below shows the temple at Luxor where some obelisks have been left standing.