- The Illusions Index (illusionsindex.org)
The Illusions Index is a fully searchable, interactive curated collection of illusions. The illusions are categorised into different types, allowing you to search for, and compare, illusions that fall under one or more type. Staff and students at the Centre for the Study of Perceptual Experience have researched each illusion to provide detailed information about what it teaches us about the philosophy and psychology of perception.
- Lock and Dam No. 7 (Wikipedia)
Lock and Dam No. 7 is a lock and dam located on the Upper Mississippi River at river mile 702.5 near the cities of La Crescent, Minnesota and Onalaska, Wisconsin. It forms pool 7 and Lake Onalaska. The facility was constructed in the mid-1930s and placed in operation in April 1937. It underwent major rehabilitation from 1989 through 2002. The lock and dam are owned and operated by the St. Paul District of the United States Army Corps of Engineers-Mississippi Valley Division.
