Tlikakila River Delta in Lake Clark National Park, Alaska

Preserving Alaska's natural beauty. Tlikakila River delta

On this day in 1980, the single largest expansion of protected lands in history doubled the size of the US National Park System. Prior to that day, Alaska had no national parks, but now the state has eight, plus numerous monuments and preserves that protect more than 157 million total acres. When President Carter signed the Alaska National Interest Lands Conservation Act, the public was granted the right to appreciate stunning locations like the one in today's photo – the braided river delta of the 51-mile-long Tlikakila River in Lake Clark National Park.

In the native Athabaskan language, Tlikakila literally means 'salmon are there river.' The park is known for its salmon-laden waterways and, as such, the fish is of major importance to the local economy and ecosystem. Local bear populations benefit from the excess salmon, and bear watching is very popular at Lake Clark. The abundance of salmon has also benefitted a wolf pack within the park – the only one in the world known to be solely dependent on salmon.