Hiking equipment
According to Tom Brown, the basic plan for survival is in the order of shelter (including clothing), water, fire, and food. Cody Lundin writes about the "Rule of 3s"; this relates to human survival without basics: three minutes without air, three hours without shelter, three days without water, or three weeks without food.
Space and survival
Many of the same existential risks to humanity would destroy parts or all of Earth's biosphere as well. And although many have speculated about life and intelligence existing in other parts of space, Earth is the only place in the universe known to harbor life. Eventually the Earth will be uninhabitable, at the latest when the Sun becomes a red giant in about 5 billion years. Mankind, or its intelligent descendants, then has to leave the Solar System to ensure survival of the human species.