Banana Ruins
From the Super Mario Wiki
Banana Ruins are ruins in Mario Kart Arcade GP that possibly belong to Donkey Kong (There is a statue of DK at the entrance of the ruins.) and may be located in Donkey Kong Island.
This course starts out in a jungle, and then goes in the ruins and then goes back out in the jungle again. At the checkpoint/finish line Diddy Kong can be seen cheering for the players.

