London had the first one in 1851 (10 letters)

{ Answer }

WORLDSFAIR

{ Related Clues }

Site of the Trylon and Perisphere: 1939

{ Tags }

first, had, london, perisphere, site, trylon, worldsfair, 1851, 1939

{ Notes }

The answer WORLDSFAIR is so rare that it appears less than once every 2500 puzzles.