The Great Pyramids of Giza are undoubtedly impressive - the perfectly constructed stone structures were built 4,500 years ago and the tallest reaches 147 metres, towering high above the flat sands of the Giza plateau in Egypt.
Even more impressive is the fact that each pyramid contains around 2 million stones, each weighing between 1.5 and 3 tonnes, and was constructed in a time when the Egyptians didn't have wheels or steel, and the only metal available was copper and copper alloys. To this day we still know very little about how they were built, or even what they housed (robots only recently gave us the first glimpse into the Great Pyramid's secret chamber)
This has led to a range of conspiracy theories on how the pyramids were built over the years, most notably the fact that they were either constructed by extraterrestrials, or slaves, captured by the Pharaohs and worked to death to make these great tombs.
But as Derek Muller explains in the new episode of Veritasium, new evidence suggests that it wasn't slaves (or extraterrestrials) who built these structures at all, it was actually skilled workers who were paid for their time and rewarded well in life and death, as recently discovered tombs near the Giza plateau suggest.
Still, even with such skilled workers it would have taken around 30 to 40 years to build the pyramids - and that's if they were working 10 to 12 hours a day and laying a 2-tonne stone every three minutes.
That's not to mention the fact that the granite they used for the internal structure of the pyramids was painstakingly chiseled out of a quarry in Aswan and then transported to Giza, more than 800 km up the Nile.
So surely they had some tools to help them do all of that? New archaeological evidence, along with hieroglyphics, suggests that the heavy stones were likely transported by giant sleds, dragged across wet sand in order to reduce friction and stop the whole thing from sinking into the desert. Other theories suggest they might have used logs of wood to make the blocks easier to roll.
There's also evidence that the Egyptians used ramps and even levers to construct the pyramids, and flood water to help level the ground they still stand on today.
But even with these limited tools and some ingenious ancient physics, is it possible that the Egyptians could have really built these awe-inspiring and mysterious shapes? Watch the latest episode of Veritasium above to find out.
And next time you look at the weathered, reddish/brown pyramids, remember that 4,500 years ago they were covered in bright white limestone and topped with a metallic mixture of gold and silver in order to look like giant sun rays. That is pretty spectacular.