Two traditions

In 1851 an American minister named Lorenzo Langstroth noticed his bees left a gap of six to nine millimetres alone: narrower, and they sealed it with propolis; wider, and they filled it with comb; in that one band, they left it clear. He patented a hive built entirely on that gap in October 1852, with frames that lift out whole instead of comb you have to cut free, and it became the hive most of the world now keeps bees in.

Britain built its own hive on the same discovery: standardised in 1946 as the British National, its brood box shallower than a Langstroth's, sized for a smaller, less prolific bee on a shorter season.

Ask an American beekeeper to draw a hive and they draw a Langstroth. Ask a British one and they draw a National. Both are stacks of movable frames built on the same 1851 idea; they only disagree about how tall a box should be.