Kate Middleton embarked on a grueling hiking challenge for charity last weekend. X/KensingtonRoyal; Instagram/princeandprincessofwales It’s a shoe fit for a princess. Kate Middleton completed the National Three Peaks Challenge last weekend, raising money for a cancer charity while scaling the highest peaks in Scotland, England and Wales in just 24 hours. And given the grueling mission requires walking a total of 23 miles, Middleton dressed for the occasion right down to her functional footwear: Scarpa’s Terra GTX Waterproof Boots. Scarpa Terra GTX Waterproof Boots Scarpa While they’re selling out fast on the brand’s website, the rugged shoes are still in stock on Amazon in all sizes (for now). Promising “out-of-the-box comfort,” the Terra is made from water-resistant leather and has a Vibr