The Lost Ruins is the second hub world in Adventure Mode. This area introduces more complex track designs and environmental hazards. To unlock the boss, Papu Papu, you'll need to collect all four Trophies from the races within this hub.
The tracks in The Lost Ruins often feature ancient ruins, jungle environments, and sometimes even lava. Pay close attention to the track layouts and look for hidden shortcuts that can give you a significant advantage. Mastering air control and landing boosts will become increasingly important here.