Mammoths still walked the earth when the Great Pyramid was being built

Wrangel Island is an island in the Arctic Ocean, between the Chukchi Sea and East Siberian Sea.
Woolly mammoths survived there until 2500–2000 BC, the most recent survival of all known mammoth populations. Isolated from the mainland for 6000 years, about 500 to 1000 mammoths lived on the island at a time.

The Great Pyramid of Giza (also known as the Pyramid of Khufu or the Pyramid of Cheops) is the oldest and largest of the three pyramids in the Giza Necropolis bordering what is now El Giza, Egypt.
It is the oldest of the Seven Wonders of the Ancient World, and the only one to remain largely intact.

Egyptologists believe that the pyramid was built as a tomb for fourth dynasty Egyptian Pharaoh Khufu (Cheops in Greek) over a 10 to 20-year period concluding around 2560 BCE.