It was founded in 1914, one of Europe's first national parks. It covers 66 square miles and preserves a variety of environments, from alpine forest and meadow to desolate rocky slopes and peaks. Unlike the United States with dozens of national parks, Switzerland has just this one, and it is well protected. There's no overnight camping or use of camp stoves or fires, biking is not allowed, and violators face a hefty fine for breaking the rules (this is Switzerland; rules are important).
What is allowed is walking and bird- and wildlife-watching on more than 45 miles of marked trails.