A Colorado man, is one of two climbers in the final push to try and scale El Capitan's Dawn Wall, in California's Yosemite National Park.
The two would make history, in a so called "free-climb" that many thought was impossible.
36-year old Tommy Caldwell, who is from the Estes Park area of Colorado, and 30-year old Kevin Jorgeson of California, are using no climbing aids---just their hands and feet to scale a sheer granite face.
Ropes are in place for protection against a deadly fall.
According to the associated press, the two are nearing the top of El Capitan and hope to complete the climb tomorrow (Wednesday) night.
For the last 17 days, Caldwell and Jorgeson have been attempting what many thought was impossible, free-climbing to the 3,000 foot summit.
The two say they've training for more than 5 years for this.
If they're successful, NBC says they will be the first since 1970 to use ropes, only as protection, in the half mile climb.