While it took Lewis & Clark 28 months to make it from St. Louis to the Pacific Ocean and back, there is only one remaining physical sign that exists to this day along the trail. That mark was left 200 years ago today when on July 25, 1806, near Billings, Mt., Capt. William Clark climbed onto a unique rock formation he named Pompey's Tower (later renamed Pompey's Pillar) and carved his name and the date. He wrote in hs journal that day:
"The wind continued high until 2 P.M. I proceeded on after the rain, lay a little, and at 4 P.M., arrived at a remarkable rock situated in an extensive bottom on the starboard side of the river and 250 paces from it. This rock I ascended and from its top had a most extensive view in every direction. This rock, which I shall call Pompey's Tower, is 200 feet high and 400 paces in circumference, and only accessible on one side, which is from the N.E., the other parts of it being a perpendicular cliff of lightish-colored gritty rock. On the top there is a tolerable soil about 5 or 6 feet thick covered with short grass. The Indians have made two piles of stone on the top of this tower. The natives have engraved on the face of this rock the figures of animals, &c., near which I marked my name and the day of the month and year. From the top of this tower I could discover two low mountains and the Rocky Mountains covered with snow."