Giant diamond

The Giant Diamond is what Martians traded their land for. Leo and Inez Wong's ancestors gave it to them to get the Occidental Hemisphere (the western hemisphere) of Mars. Many generations later, they assume it is a worthless bead, so they wanted their land back. They kidnap Amy, which Kif Kroker, Fry, Leela, Bender and Zapp Brannigan teamed up for a rescue mission. But when the Martians saw Kif flying a Buggalo, he was taken to smoke the peace pipe, unfortunately, Kif was not a big smoker, and "coughed at their offer". This offended the Martians to the point that they wanted to kill him with the "bead". Upon seeing the "bead" everyone realizes that it's a giant diamond. The Martians decided to forget their land and go to look for a new planet.