Highway 20 was designated a federal highway in 1926, and until the arrival of the Interstate Highway System in the 1950s it was a primary route across northern Wyoming. From the Great Plains in the east to the mountains in the west, Highway 20 passed though cities and towns that retain their frontier visages and such wonders as Hell's Half Acre, the Wind River Canyon, Natural Hot Springs, Buffalo Bill Scenic Byway, and spectacular Yellowstone National Park. Fortunately, historic Highway 20 remains almost completely intact and can be driven much as travelers did in years past. Postcard History Series: Along Wyoming's Historic Highway 20 celebrates this trip, illustrated by more than 200 vintage postcards showing the personality of the road. Not to be forgotten are the tourist courts, hotels, diners, and gas stations that made automobile travel possible.