Carlsbad Caverns
From Memory Alpha, the free Star Trek reference
Carlsbad Caverns are a unique set of caves on Earth in New Mexico.
While T'Pol was stationed in Sausalito, she took a five-day leave, visiting the Carlsbad Caverns, along with Yellowstone National Park, and Carbon Creek, Pennsylvania due to 'scientific interest.'
Later in 2152, after telling a story about her second-foremother T'Mir, T'Pol listed the Carlsbad Caverns among the places she visited while on leave on Earth. (ENT: "Carbon Creek")
