Sometimes, your 10-hour movie adaptation of Frank Herbert’s novel Dune—set to star Mick Jagger, Salvador Dalí, and Orson Welles—simply never ends up panning out (looking at you, Alejandro Jodorowsky).

For every building built, painting painted, and film filmed, there are countless others that fall by the wayside for some reason or another. On this episode of The List Show, Mental Floss editor-in-chief Erin McCarthy has scoured the margins of history to tell the most fascinating stories of projects left unfinished. Perhaps unsurprisingly, the Grim Reaper is often to blame; Jane Austen gave up on Sanditon not long before her death, and Franklin D. Roosevelt passed away the same day Elizabeth Shoumatoff was trying to paint his portrait. Other projects proved too expensive to finish—like Cincinnati’s subway system.

So what happens to all the novels with no endings and tunnels with no trains? Press play below to find out, and explore other episodes of The List Show on the Mental Floss YouTube channel.