Automaker Daimler is seeking to revitalize its luxury Mercedes-Benz brand by rolling out a new $1 million S-Class Pullman in 2015. Reminiscent of the famous 600 Pullman—“The Grand Mercedes” once used to ferry celebrities, world leaders, and popes—the new vehicle is meant to challenge rivals BMW and Audi in the increasingly crowded luxury car market. It also will help burnish Mercedes’s upmarket cred at a time when it’s churning out cheaper vehicles for the U.S. market.