'Mountain' in the Bible

Six days later, Jesus took Peter, James, and John and led them up a high mountain to be alone with him. His appearance was changed in front of them,

On their way down the mountain, Jesus ordered them not to tell anyone what they had seen until the Son of Man had risen from the dead.

I tell all of you with certainty, if anyone says to this mountain, "Be lifted up and thrown into the sea,' if he doesn't doubt in his heart but believes that what he says will happen, it will be done for him.