The dream of sending humans to Mars is closer than ever before. In fact, many scientists think that the first person to set foot on the Red Planet is alive today. But where should the first explorers visit when they get there?　　Horizon has gathered the world's leading experts on Mars and asked them: where would they go, if they got the chance - and what would they need to surviv...

讲述一个看门人被困在一个女厕所，遇到一批僵尸的攻击……