A-bomb shelters, commonly known as bomb shelters, are structures designed to provide protection to people during a nuclear attack. They can be constructed above or below ground and have been used in various forms throughout history. Synonyms for a-bomb shelters include fallout shelters, blast shelters, nuclear shelters, protection shelters, and emergency shelters. These synonyms have a variety of connotations, but all imply a safe space in which to seek refuge during a catastrophic event. While the threat of nuclear war has diminished in recent years, many people continue to build or use a-bomb shelters as a precautionary measure or for emergency preparedness.