Obelisks were prominent in the architecture of the ancient Egyptians,
who placed them in pairs at the entrance of temples. The word "obelisk"
is of Greek rather than Egyptian origin because Herodotus, the Greek
traveler, was the first to describe the objects. Twenty-eight ancient
Egyptian obelisks are known to have survived but only eight still reside
in Egypt.

The Egyptians built them out of a single quarried stone and are so heavy
they have been extremely difficult to transport and re-erect.
(A real credit to the technology and engineering of the ancient Egyptians).

This obelisk (23 m / 75 ft ) is decorated with hieroglyphics
exalting the reign of the pharaoh Ramses II

from: Wikipedia