An ancient city stood at the site of the present village of Poli. You can see the crumbling acropolis, Byzantine castle and church.
As mentioned above, there was a massive Turkish massacre, with all the men killed and women and children taken as slaves. The few Kassiots who survived remain here, or emigrated to Egypt to work on the Suez Canal. Many have moved to America.
If you want to be able to brag that you took the world's shortest scheduled flight, take the plane from Karpathos to Kassos. It's a five minute trip. See more photos of Kassos.