Glacier National Park is famous for its Going to the Sun Highway.  I wasn't able to travel this route as it will be a few days until it opens for the summer.

The Rocky Mountains gradually recede as I travel out into the Great Plains

Marias Pass  -  A watershed moment on my trip (sorry for the unfortunate pun).  Pour a glass of water on the west side of this continental divide and it will eventually end up in the Pacific Ocean, do the same thing a few steps to the east and it will flow into the Atlantic.

This monument marks the spot where Captain Lewis of the Lewis and Clark Expedition discovered in 1806 that the headwaters of the Marias River lay to the west instead of the north as he and his party had hoped.  If the geography had been different, the 49th latitude border between Canada and the United States would be further to the north.

I spent much of the afternoon traveling through Blackfeet territory, one of the great tribes of the American plains.