Actresses Dorothy Sebastian and Joan Crawford enjoy some hamburgers on a Los Angeles beach, c1925. (Credit: Getty)
Why are they called hamburgers?
From the grilled, minced beef patties that originated in the German city of Hamburg and that were introduced to America in the 19th century by German sailors or immigrants.
Where was the hamburger first commercially served in America?
Predictably, many places are keen to claim this honour.
The argument is complicated by disputes over what actually constitutes a hamburger.
For example, does it have to be in a bun?