As the saying went, all roads once led to Rome — and scientists now say those roads stretched 50% longer than previously known. A new study combines information from historical records, ancient journals, locations of milestones and other archival data with newly available satellite imagery to map all known roads in the ancient Roman Empire. Researchers say these feats of Roman engineering still shape the geography and economy of the Mediterranean region and beyond. The new dataset and digital map are available online for scholars, history teachers and people with an interest in ancient Roman history. Results were published Thursday in Scientific Data.