Quick one today, because apparently I've decided to spend the morning napping. In the 1970's, the just-born EPA hired freelance photographers to catalog the state of the country at that point, during the period spanning from 1971-1977, though mostly towards the start of that timeline. Some 15,000 pictures were taken in a project dubbed "Documerica", many highlighting environmental issues of the day.
Those pictures then more or less sat dormant, until now. You can view them here, picturing every state save North Dakota. The difference between then and now is stark:
*These are the San Gabriel Mountains, just north of Los Angeles, in 1972.
*Lest you think I'm just picking on Los Angeles and going after the low-hanging fruit, here's Tacoma, Washington, also in 1972.
*And Boston, Massachusetts in 1973.
*And Salt Lake City, Utah in 1972.
*Or Louisville, Kentucky in 1972. I promise you there's a city in there somewhere.
*The Maid of the Mist boat at Niagara Falls in 1973 is seen here amidst built-up foam. The foam is not from the falls. It's sewage waste.
*Or to take waterfalls completely out of the equation, here's the Colorado River in 1972.
*Here's an illegal dumping area just off the New Jersey Turnpike, taken in 1973.
*This looks to be an area outside Ogden, Utah, in 1974.
*The Moab, Utah city dump when it closed in 1972. It sits 15 miles from one national park and three miles from another one.
*And, of course, the Cuyahoga River. This picture was taken near Jaite, Ohio, south of Cleveland, in 1975. What are those in the background dipping into the river? Cars.
Documerica has no pictures of the Cuyahoga being actively on fire. That was because it caught fire in 1969, before the project, though that fire was a major factor in the EPA's creation.
EDIT: Apparently, none of those later links actually work, as they came from live search results that worked for me at the time I looked at them but no longer do. The first link, the one leading to the entire archive, does work. You'll have to go to that. Sorry.