Complex sentence: The Gibraltar Rock State Natural Area became a Wisconsin-designated natural area in 1969, when it was originally owned by the county until 2007, when they transferred ownership to the Wisconsin Department of Natural Resources (WDNR).
Split into simpler sentences: The Gibraltar Rock State Natural Area became a Wisconsin-designated natural area in 1969. It was originally owned by the county until 2007, when they transferred ownership to the Wisconsin Department of Natural Resources (WDNR).