The Pearl District in Northwest Portland, which was largely occupied by warehouses, light industry and railroad classification yards in the early to mid-20th century, now houses upscale art galleries, restaurants, and retail stores, and is one of the wealthiest neighborhoods in the city. Areas further west of the Pearl District include neighborhoods known as Uptown and Nob Hill, as well as the Alphabet District and NW 23rd Ave., a major shopping street lined with clothing boutiques and other upscale retail, mixed with cafes and restaurants.