Greenland’s Grand Canyon
Greenland’s Grand Canyon or Grand Canyon of Greenland is a tentative canyon of record length discovered underneath the Greenland ice sheet as reported in the journal Science on 30 August 2013 , by scientists from the University of Bristol, University of Calgary, and University of Urbino, who described it as a mega-canyon. https://www.newstriger.com/the-ice-canyon-in-greenland/