 He is best known for his research in Egypt including excavations in the Valley of the Kings where he investigated the long-neglected undecorated tombs in the royal cemetery.His work there resulted in the rediscovery of the lost and controversial tomb KV60, the re-opening of the long-buried KV21 with its two female and likely royal occupants, and tombs KV27, KV28, KV44, KV45 and KV48.In 2017, he rediscovered three small tombs (KV50, KV51 and KV52) in the Valley of the Kings which when first encountered in 1906 contained the mummies of animals including a dog and monkeys.