Five thousand years ago, a spectacular waterfall stood near here on the Mississippi River, throwing spray and thunder as it slowly carved the river's only true gorge. Over centuries the falls moved upstream and shrank, awing pre-historic bison hunters and later generations of people. The gorge seen today was created as the remnant of a much greater falls that once roared beside the current site of downtown St. Paul and later became modern St. Anthony Falls in Minneapolis. As falling water eroded soft sandstone beneath layers of sedimentary bedrock, the limestone caprock collapsed piece by piece into the river below, causing the waterfall to recede upstream. In 1817, Stephen Long vividly described the Mississippi River Gorge as a place of cascades, roaring current, and the majestic cataract of the Falls of St. Anthony. Geologist Newton H. Winchell first calculated the erosion rate of the waterfall in the late 1800s, and geologists today consider his estimates quite accurate. Two centuries ago, Dakota Indians and European trappers traveling the gorge in spring encountered powerful rapids, foam and spray around green islands, and abundant wildlife including giant sturgeon, catfish, paddlefish, and eagles. By the 20th century, economic ambitions reshaped the river: a first lock and dam was built in 1907 below former Meeker Island, and the larger Lock and Dam #1, completed in 1917, flooded the gorge for barge traffic and hydro-electricity, submerging or removing many islands so that Pool #1 replaced the great rapids.
