I am currently in a long term Civilization game with a few of my friends. During our previous session I was one single turn away from a science victory, however, the warmonger among us managed to destroy my only city (due to one-city-challenge being on) with his superior fleet. Luckily for me, complete kills is also on, and I still have a decent army. Is it possible for me to capture a landlocked city-state, construct the final piece of the spaceship, and win the game?
It seams the answer is NO. One-city-challenge likely refers to one city overall and not one city at a time. In "Brave New World", capturing a city on one-city-challenge seams to remove it regardless to weather your original capital still exists or not.