Ancient Greeks and Romans had pretty advanced science – and we know quite a bit about it. The two pieces referenced today will expose you to both what we know and how we do.
First an article about how we know what we know about Roman legions. This is extracted from Adrian Goldsworthy’s excellent The Complete Roman Army. That is an excellent book all by itself and highly recommended for anyone interested in the Roman army, but the extract focuses on the various sources we have and their value. This is as good a review as any, and helps explain how the study of history is conducted.
As a side note, here is a 2 minute video of how to identify remains of Roman forts by aerial photography, and another 5-minute clip on the reconstruction of Roman forts from ground remains.
The main feature I want to draw your attention to, is a lecture by Dr Richard Carrier about the extent of science that the Greeks and Romans had access to. Dr Carrier is an ancient historian, and this lecture is excellent. He quickly goes over the various areas of science and technology (astronomy, engineering, medicine, etc) that were used in ancient times. The lecture itself is 45 minutes (the rest is Q&A), and will leave you flabbergasted.