The showdown of the "centuries" was released August 11, 1962. King Kong vs Godzilla brought two of the world's favorite giant monsters together. I haven't seen it yet because I haven't found an English version yet, but the synopsis at imdb.com suggests that a pharmaceutical company captures Kong and takes him to Japan. Maybe it's the drugs what made him so big? And Godzilla has never been captured so why does he not...I'd better stop. I saw Toho's reason for the ending but let's just say Godzilla is probably more popular now than Kong is.