Stock photography, photos: Panama Canal mules tow a cargo ship Stock photos of Two Panama Canal mules tow a cargo ship during its transit thru the Miraflores Locks. - 05/2004 - © Humberto Olarte Cupas / PanamArts Photograph: © Humberto Olarte Cupas Click for a larger image and more information Keywords associated with this stock photo: Panama Canal, Miraflores Locks, Mules, cargo ship, containers, transit, rain, weather, climate, 24/7