National Survival: My Shelter Can Be Infinitely Upgraded

When they woke up, billions of people were transported to a world of doomsday cataclysm. Everyone guards a shelter and needs to survive in a harsh environment. Under the extreme cold and supplies are scarce, even going out to explore can be enough to lose your life! Fortunately, Ye Yi activated the system and could infinitely upgrade his shelter and strengthen himself. Civil shelters—concrete shelters—steel shelters—alloy shelters… Rock retaining wall-steel retaining wall-alloy wall-tungsten steel courtyard... Physical power generation - wind power generation - radiation power generation - reactor power generation... … While everyone was worrying about a mouthful of food, Ye Yi already had so many supplies that he couldn't even put them in the warehouse. When everyone cheered for stepping out of the shelter, Ye Yi had already searched for resources within a hundred miles. When people saw Ye Yina's shelter, which looked like a technological castle in the future, they couldn't help but marvel: "We are here to survive in this apocalypse." "You're here for vacation, right?" This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.