The Earth shoe (also known as the Kalsø Earth Shoe) was an unconventional style of shoe invented in the 1970s in Scandinavia by Danish yoga instructor and shoe designer Anna Kalsø. Its unique Negative Heel Technology design featured a sole that was thinner at the heel than at the forefoot, so that when wearing them, one walked heel-downward, as when walking in sand, with various claimed health benefits.
The shoes were introduced in the United States in New York City on April 1, 1970, three weeks before the first Earth Day.
The shoes surged in popularity and were prominently featured on The Tonight Show Starring Johnny Carson and in TIME Magazine. When the manufacturer of Kalsø Earth Shoes was unable to keep up with demand, franchise owners pursued litigation against the United States distributor. Retail sales of the brand in the U.S. were discontinued by the late 1970s.
In 2001, Kalsø Earth Shoes re-surfaced after the rights to the name, technology and branded properties were purchased by Meynard Designs, Inc.