In modern American beekeeping, a Langstroth hive is any vertically modular beehive that has the key features of vertically hung frames, a bottom board with entrance for the bees, boxes containing frames for brood and honey (the lowest box for the queen to lay eggs, and boxes above where honey may be stored) and an inner cover and top cap to provide weather protection. In a Langstroth hive, the bees build honeycomb into frames, which can be moved with ease. The frames are designed to prevent bees from attaching honeycombs where they would either connect adjacent frames, or connect frames to the walls of the hive. The movable frames allow the beekeeper to manage the bees in a way which was formerly impossible. The key innovation responsible for the hive's design was the discovery of bee space, a gap size of between in which bees would not build comb, nor would they close it with propolis. Modern Langstroth hives have different dimensions from L. L. Langstroth's beehive that was originally patented in 1852 and manufactured until approximately 1920, but retain the main features of allowing bee space as well as easy access which works well for the bees but also makes management of the beehive easier for the beekeeper. The standard beehive used in many parts of the world for beekeeping is based on the Langstroth hive. History Before the dimensions of bee space were discovered, bees were mostly hived in skeps (conical straw baskets) or gums (hollowed-out logs which approximated the natural dwellings of bees), or in box hives (a thin-walled wooden box with no internal structure). In 1851, the Reverend Lorenzo Lorraine Langstroth (1810–1895), a native of Philadelphia, noticed that when his bees had less than but greater than of space available in which to move around, they would neither build comb into that space nor cement it closed with propolis. This measurement is called bee space. During the summer of 1851, Langstroth applied the concept to keeping the lid free on a top-bar hive, but in autumn of the same year, he realized that the bee space could be applied to a newly designed frame which would prevent the bees from attaching honeycomb to the inside of the hive box. Attaching comb to the hive wall was a difficulty with frameless designs, such as Dzierżon's frameless movable-comb hive (1835). US Patent 9300 was issued to Langstroth on