Bootleg Canyon, Boulder City, Nevada.
Basically there was a gravel road up the middle of these 2 gigantic hills with singletrack carved into their sides. Very "flow-ee" but also very technical with extremely loose dirt and numerous boulders and rocks to pick through. Also, because there were over 4,000 people out riding you had to be alert to other riders coming up behind you and at you.
On the Norco Team Carbon. Brand new SRAM XX group. I think this bike was under 20lbs.
On our road ride testing out the new Dura Ace electric shifters on Orbea Orca full carbon roadies.