Yellowstone National Park, WY - UNESCO World Heritage Site

 Place: Yellowstone National Park

Weather: A mix of clouds and sun early, then becoming cloudy later in the day, 46/78F.

Route: From Devils Tower 399 mile west on US-14 W, I-90 W, US-16 W, US-20 W, WY-30 W, US-14 W.

Significance: The granddaddy of them all. In 1872 it became the nation's first national park.  It is also one of the most interesting parks. There are countless hydrothermal and geologic wonders, as well as incredible animals who seem to know be very comfortable showing themselves off to guests.  

Websites: UNESCO World Heritage Site, National Park Service.

Images: 

Grand Canyon of Yellowstone (from travelwyoming.com)

Hot springs (from nationalgeographic.com)