O.R. Tambo International Airport
Facts on JNB
Johannesburg's airport has been renamed twice since it opened in 1953 -- first from Jan Smuts International to Johannesburg International in 1994, then to O.R. Tambo International in 2006 to honor anti-apartheid leader Oliver Tambo -- yet its IATA code has always stayed JNB.
Source: Wikipedia
Because the airport's identity code was locked in decades before its current name, JNB doesn't spell out 'O.R. Tambo' or even obviously match a current name at all -- a reminder that airport codes, once assigned, are almost never changed even as the buildings around them are renamed for new heroes.
Source: Wikipedia