LONDON, ENGLAND—Archaeologists digging sites in London ahead of the construction of a high speed railway continue to find remarkable artifacts. Some of their latest discoveries are three Roman horseshoes that were cast off some 2,000 years ago. They were found in the ruts of an ancient Roman road in the vicinity of the modern-day Liverpool Street station. Made of metal, the horseshoes would have been fastened to the hooves with leather straps.