andy goldsworthy is a British sculptor, photographer and environmentalist living in Scotland who produces site-specific sculpture and land art situated in natural and urban settings. His art involves the use of natural and found objects, to create both temporary and permanent sculptures which draw out the character of their environment. (from wikipedia).
if you are interested, i recommend checking out videos on andy goldsworthy. pretty fascinating process. there are also many books featuring his work, but i find the videos particularly intriguing.