After stepping all over the earth, shoes can only hope to avoid the planet’s revenge by becoming sustainable or requisitioning hoverboards. Give feet a chance with today's Groupon: for $20, you get $50 worth of sustainable shoes at Birkenstock of San Diego. Choose from the following locations: Coronado, Lemon Grove, San Diego, Encinitas, or Palm Springs.

Although the business started out slinging only Birkenstock sandals, Birkenstock of San Diego now fits shoppers with shoes from more than 30 manufacturers that divide their consciousness equally among style, the environment, and foot comfort. Birki's Pacific sandal ($44) combines waterproof durability and fashion sense even more effectively than monocle goggles, conjoining a contoured foot bed and strap in a single synthetic mold and available in 10 vibrant colors. The women’s Gizeh Birko-Flor sandal by Birkenstock ($79.95) straps in nubs with your choice of chic materials and leaves toes free to tickle passing toddlers. Less intrusive than a regular shoe and more protective than bare feet, Vibram FiveFingers ($74.95–$124.95 for adults; $59.95 for kids) nestle each little piggy into its own home, allowing the foot to spread more naturally, reducing stress on the knees, hips, and lower back, and dropping the heel just enough to encourage extra stimulation of leg muscles. Simple crafts sustainable shoes such as the men's Flippee vegan sandal ($29.95), which finally releases diet-conscious dogs from the guilt of their shoe-snacking impulses.