Diet Cola Mountain

Diet Cola Mountain is a large mountain towering over Sugar Rush. It seems to be an unfinished bonus track (as shown by the nearly constructed pink wafer bridge) and was the home of Vanellope, having a secret entrance known only by Vanellope herself. Its secret entrance is between two sugar free lollipops.

Official Bio
"Sugar Rush is full of sweet sites, but the most colossal candy attraction is Diet Cola Mountain. It may look peaceful, but watch out for fizzy explosions and sugary surprises!"

Trivia

 * This is a reference to the reaction between Diet Coke and Mentos as there are Mentos at the top.
 * The Cola in the mountain "is boiling hot", so when the Mentos hit the cola, the splash it creates is scalding.
 * The interior of the volcano seems to be made out of pretzel.
 * After its eruption, its implied the volcano destroyed much of its surroundings. When the game reset, however, everything was presumedly altered to its natural state.