During the Corp of Discovery's famous expedition to explore the Louisiana Purchase, Captain William Clark and his trusted guide Sacajawea, stopped at a large rock formation in Southeast Montana to rest near a grove of trees by the Yellowstone River. As Captain Clark was ascending the large rock tower, he noticed several petroglyphs and pictographs from Native American tribes on the rock and decided to carve his name and the date in the stone, 'Wm Clark, July 25, 1806'. Sacajawea had been carrying her baby boy Pomp in a cradleboard as they traveled by canoe. Captain Clark had a soft spot in his heart for the toddler and affectionately named the rock, "Pompeys Tower". Today, we know this as "Pompeys Pillar". This remains the only engraving purposely left behind by the expedition. The Pompeys Pillar Historical Association desperately needs funding to continue education and enrichment programs for future generations and to protect this National Monument.