Stacy wrote a neat post about 5 ancient technologies that are suspiciously very, very modern but I made a mistake and published it in the past! (If you're wondering, it's a matter of me forgetting to update the article's publication date). So, mea culpa, Stacy! Instead of re-publishing the piece, let me just do a meta-post :)
Here it is:
A jet engine in the first century B.C.? Perhaps. A jet engine in the first century A.D.? Definitely. The aeolipile is a rocket style jet engine that spins when it’s heated and is the first-ever device known to use steam for a rotary motion. Although it was “invented” in 1698 by Thomas Savery, the original may have been invented in the first century B.C. Roman architect Vitruvius’ De architectura, a work on then-modern architecture written around 25 B.C., includes a device called the aeolipile. However, it has never been verified that his aeolipile (which translates to “ball of Aeolus,” who was the god of the wind, so it’s kind of a generic name that could apply to various inventions) was the aeolipile that we know existed in the first century.
That’s the aeolipile that Hero of Alexander wrote about, including a detailed description of how to construct one. The invention credit is usually given to Hero instead of Vitruvius.