If you saw the fairly recent Tom Scott video in which he got to operate a trebuchet, you may find the video above interesting. Back in the early 1300s, King Edward laid siege to a castle and ordered the building of a gigantic siege engine to knock down its walls. To see whether such a thing was possible, several decades ago the PBS Nova program recruited teams of builders to attempt to construct trebuchets large enough to fling 250 lb (113 kg) balls a distance of 200 yds (183 meters). And if building such giant trebuchets was possible, they also wanted to see if it would be capable of taking down a castle wall.

precious cube child

Imagine a world where your furry best friend could tell you exactly what they're thinking. A growing number of dog owners claim this is already happening, thanks to innovative word buttons that seem to unlock a new realm of canine communication. But are these dogs truly understanding what we’re saying — and talking back? Are they really thinking creatively, applying words in new contexts? Or is this just clever conditioning? To find out, scientists are conducting the largest animal communication study in history, analyzing millions of button presses from thousands of dogs worldwide.

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NOVA: Danger in the Jet Stream (1997)

This special created just before the Viking missions to Mars is about scientists trying to understand how life on Earth may have begun and if the same processes could have occurred on other planets. With Carl Sagan, Viking, and the Miller–Urey experiment all featured, it's a bit like a prototype of the Cosmos episode "One Voice in the Cosmic Fugue", which came out four years later.

Snakebit by design issues, politics, funding problems, the Challenger disaster, and even the threat of terrorism, the Galileo mission to Jupiter almost didn't happen. Originally scheduled for launch in 1982, it would only leave Earth in 1989, two years after this program aired. Despite other in-space problems, ultimately the mission was a success, studying the giant planet for eight years until being deorbited into Jupiter in 2003.

Oh hey it's free on YouTube now, if your state/location hasn't got it streaming on a PBS site for free.