The word sanctuary has religious roots, and can refer to a temple or church, but its use has broadened to include anywhere people go for peaceful tranquility or introspection. Your pickup truck might be your sanctuary if that's where you can clear your head.
Historically, a sanctuary is the holiest of holy places — a temple or church. Now, it's a word for anywhere a person feels especially safe and serene. People might call their homes their sanctuary, or a beautiful spot in a quiet woods can be described as a sanctuary. It can also be a way to refer to shelter or asylum from political danger, such as: "The forbidding jungle can offer sanctuary to the guerrilla rebels."