The design of the modern hive rests on a single key discovery: bee space. Bees will not fill a gap of about \(3/8\) inch (\(\sim 9.5\) mm) with wax or propolis. Lorenzo Langstroth exploited this principle in 1851 when he invented the Langstroth hive, the most common modern hive, which uses movable frames hung inside stackable boxes. Other designs include the top-bar hive, a horizontal hive without full frames, the Warre hive, a vertical hive resembling a tree hollow, and the Flow hive, a modern hive with built-in honey extraction that remains controversial among traditional beekeepers.
Inside a Langstroth hive, the deep hive body, also called the brood box, houses the brood nest. Above it, the beekeeper adds supers, shallower boxes used to store honey; a medium super is a common choice because it is lighter to lift. Each box holds frames, wooden or plastic rectangles that contain the comb. Bees can be guided in their comb-building by foundation, a wax or plastic sheet impressed with cell patterns, or allowed to build natural comb in foundationless beekeeping. A queen excluder, a grid sized so that workers pass through but the queen cannot, is sometimes placed between the brood box and the honey supers to keep brood out of the honey harvest.
Other essential components include the inner cover, a board between the top super and outer cover that supports ventilation, and the outer cover, the weatherproof top of the hive. The bottom board forms the base and can be solid or screened; a screened bottom board supports varroa monitoring and ventilation. An entrance reducer is a wooden block used to narrow the hive entrance, helpful when defending against robbers or in cool weather. To work safely, beekeepers wear protective gear including a veil, a suit or jacket, gloves, and boots. Two tools are indispensable during inspections: the smoker, which generates cool smoke to calm bees by masking alarm pheromones and triggering them to gorge on honey, and the hive tool, a flat metal lever used to pry frames apart and scrape wax or propolis.