Once dependent almost solely on the mining industry—in the early 1900s it was called "the richest hill on earth" because of the valuable ores that lay beneath it—Butte, like many older American cities, is in the midst of a transition toward a more diversified economy. With easy access to western and midwestern markets, Butte is one of the west's major transportation hubs; the city is also moving into enterprises related to energy research and high-altitude sports training. Despite the changes underway, Butte retains its multiethnic heritage and its connection to the breathtaking natural beauty of the surrounding Rocky Mountains. For statistical and other purposes, Butte is traditionally linked with Silver Bow County.