The Orion Layout of Giza
The hypothesis of this alignment came from Robert Bauval, was the basis a best selling-book, and is well-received by alternative researchers due to the apparent accuracy, and the definite simplicity – the belt of Orion is the same pattern as the three pyramids of Giza. Two large, one smaller, not quite in alignment.

The primary academic dismissals are:
The alignment pattern is upside down. This was already anticipated and explained by Bauval, the mirror image is due to the Egyptians looking at the stars in reflecting pools, and/or it is relative to the Nile as the Milky Way.
The dating of the Sphinx to 10,500 BC. This is a stretch and worthy of debunking. The purpose was to propose an ancient date for the Sphinx (thanks to weathering evidence) that matched how those three stars looked at that time. Star alignments are almost never proven evidence for antiquity. Weathering data should be looked at on its own merits.
It is not hard to see why academia is skeptical, until you look at the layout of Teotihuacan…
The Orion Layout of Teotihuacan
This is where we can struggle to prove a connection if this was the only global connection to be made. The alignment is the same as at Giza, but only if you accept that the platforms are what count sizewise (and not the pyramids upon them), and/or the Citadel at the bottom was designed to have another large pyramid upon it, but is was never built. The design is what counts!

Comparison of Alignments

Dimensions of Pyramids
It becomes much less of a coincidence, and more of a global intent, when we look at the dimensions of the world’s largest pyramids.
Giza – Great Pyramid
Height Original with casing: 146.6m.
Height Current without casing: 138.5m.
Base 230.25m to 230.45m
Giza – Pyramid of Khafre
Height Original with casing: 143.5m.
Height Current without casing: 136.4m.
Base 215.5m each side
Fun fact – the Khafre pyramid is on fractionally higher ground than the Great pyramid, and it accepted that they were meant to appear to be the same height.
Teotihuacan – Pyramid of the Sun
Height Original before erosion: 66m.
Height Current after erosion: 63m.
Base 220m x 230m
The largest pyramids at both sites having the same extraordinary longest side of 230m is hard to wave off as a coincidence!
China – Mausoleum of Qin Shi Huang
Height Historical writings 120+m
Height Current after erosion 47–76m
Base 345m × 350m