Raleigh is home to North Carolina State University and is part of the Research Triangle area, together with Durham (home of Duke University) and Chapel Hill (home of the University of North Carolina at Chapel Hill). The "Triangle" nickname originated after the 1959 creation of the Research Triangle Park, located in Durham & Wake Counties partway between the three cities and their universities. The Research Triangle region encompasses the U.S. Census Bureau's Raleigh-Durham-Chapel Hill Combined Statistical Area (CSA), which had an estimated population of 2,037,430 in 2013. The Raleigh Metropolitan Statistical Area (MSA) had an estimated population of 1,214,516 in 2013.
Try to answer this question if possible (otherwise reply "unanswerable"): When did the Triangle stop existing?
unanswerable