World most famous opening?


There is no World's Most Famous. Trends go in and out.
In the 1950s, it would be the French Defense.
In the Fischer/Spassky era, the Kings Gambit was popular.
By the 80s, it was the Caro-Kann
During the years of Kasparov, it was the Scheveningen (via the Najdorf move order)
In the 2000s, it was the Berlin
By the teens, it was the Sveshnikov
Etc etc