How tall, in meters, was the Great Pyramid of Giza when it was completed (original height, including its now-lost capstone)?

Answer

146.6 meters

It was the tallest human-made structure on Earth for over 3,800 years, until Lincoln Cathedral's spire overtook it around 1311 AD. Erosion and the loss of its casing stones have shaved it down to about 139 meters today.

Source: Encyclopaedia Britannica