The term 'Rumble in the Jungle' refers to the famous boxing match between Muhammad Ali and George Foreman that took place in Kinshasa, Zaire (now the Democratic Republic of Congo) on October 30, 1974. The two crossword solutions, GROWL (5 letters) and PURR (4 letters), are both words used to describe the sound of animals. GROWL is a deep, guttural sound made by animals such as dogs and bears, while PURR is a low, vibrating sound made by cats and other felines. Together, these two words can be used to describe the atmosphere of the Rumble in the Jungle, which was a highly anticipated and exciting event.