The closest you can get without digging is 3963 miles while the farthest you can reach while staying on ground is 3979 miles.

The shape of Earth is not perfectly spherical - the distances vary by 15 miles. The poles are farther while the equator is closer. If you decide to dig down, the average temperature increase would be 40 degrees Fahrenheit per every mile. However, it is not recommended because if you do reach the core, you would experience 7000 degrees of heat on your body.

Our planet is believed to be more than 4.4 billion years old. Some researches calculated that Earth appeared 10 millions after the Sun did!