Practical Engineering on Roman concrete. The TL;DR is that we are far more advanced. https://youtu.be/qL0BB2PRY7k?si=kqiyxOTLBQw9h4_F
We do know how to make Damascus steel: https://youtube.com/shorts/1DNWLZ8IiMQ?si=c4-Ch7C3Q_6zcYoi
This fellow says we don't know how to make the historical Greek fire but acknowledges we can make identical substances: https://youtube.com/shorts/wiHXE6lhLmo?si=OPEjW40cck5aQAsv
We could build the Great Pyramid today using modern methods in 5 years using 2000 workers and $5 billion USD vs historical 20 years and 10s of thousands of workers: https://www.livescience.com/18589-cost-build-great-pyramid-t...