The antipode of any spot on Earth is the point on the Earth’s surface that is diametrically opposite. If you drilled straight down through the planet from the Highlands (below) and came out the other side, where would you end up? Scroll down to see.
You’d come out in the Indian Ocean about 750 miles southwest of Australia. By one estimate, only about 15 percent of the land on Earth is antipodal to other land. See below for a video tour from one spot to the other via Google Earth.