Angkor Wat was and is a prime example of human civilization and its early prowess. However, the title is not entirely right. The Angkor Wat by itself was built by Suryavarman who was apparently a descendant of the Cholas of Tamilnadu, India. The Cholas and Pandyas are very under documented empires.
Some examples of what the Cholas and Pandyas accomplished which stands to today are
Tanjore Temple (Cholas)
https://www.youtube.com/watch?v=XX9-__GWHnA
(Edit: Unfortunately, this video also has a lot of old western cliched ideas of Hinduism, hope I had a better documentary to share...)
(for scale, this can fit 200 Taj Mahals)
https://www.britannica.com/biography/Suryavarman-II
There are tamil inscriptions in Angor Wat and the architecture is highly influenced by Chola/Pandya architecture.
https://www.quora.com/How-did-Tamil-Kingdoms-influence-Angko...
Some examples of what the Cholas and Pandyas accomplished which stands to today are
Tanjore Temple (Cholas) https://www.youtube.com/watch?v=XX9-__GWHnA (Edit: Unfortunately, this video also has a lot of old western cliched ideas of Hinduism, hope I had a better documentary to share...) (for scale, this can fit 200 Taj Mahals)
Madurai Meenakshi (Pandyas) https://www.youtube.com/watch?v=iQjI3DPt9Tk
You can see that the architectural pattern of 4 directional gateways with a central temple complex is basically the same as Angor Wat.