Watch Sweetwater Junction (1980) : Full Movie Online Free Texas is the homeland of the Western diamondback rattlesnake, a plague to cattle, oilpipe engineers and everyone not on the alert. At Sweetwater’s annual Rattlesnake Round-Up - the largest in the world – only live snakes are brought in, to extract the venom needed for medical research. Thus, ingenious and scrupulously delicate hunting techniques are developed.