Answer/Explanation
The US sought to defend its eastern border from attack and drive Spain from power in the Americas.
General Zebulon Montgomery Pike (1779-1813) was a contemporary of Lewis and Clark and he was an early explorer of the territory of Louisiana and the area around the Arkansas and the Red rivers. He also trekked across the Great Plains and the Rocky Mountains, and he published his findings in a book. Pikes Peak, in Colorado, was named in his honor, although he was not able to reach its summit.
I've heard the Ganges River is very polluted and filthy. Indians throw trash in there. It was known for its beauty. People bathed in its waters believing it was holy. That is one reason it is so dirty. It would take a very long time considering the fact that the Ganges River is one of the longest in India, with the Indus River at first place.