La Piedra Del Peñol (The Guatapé Rock),is a 70 million yr old monolithic formation located at Guatapé,(86km N.E of Medellín, 2 hrs by bus) in Antioquia, Colombia.It  rises from the bottom of the hydroelectric dam of Peñol-Guatapé.It is a border landmark between farms &amp; cities.  At its highest part, on the rear (southeast s