It's not quite the Grand Canyon, but a recently discovered ancient subglacial trench underneath Antarctica has one thing over the wonder of the world: it's almost twice as deep.

Using data from satellites and ice-penetrating radars, scientists have now released the first detailed chart of the Ellsworth Subglacial Highlands.

"The discovery of this huge trough, and the characterization of the surrounding mountainous landscape, was incredibly serendipitous," said Neil Ross from Newcastle University, the lead author on the paper detailing the Highlands, 

The 185-mile-long Ellsworth Highlands lie in West Antarctica and reach depths of up to 1.85 miles, with more than a mile beneath the sea floor. The Highlands can also reach a width of more than 15 miles. By comparison, the Grand Canynon measures approximately 277 miles long, up to 18 miles wide, and over one mile in depth at some points.

"To me, this just goes to demonstrate how little we still know about the surface of our own planet. The discovery and exploration of hidden, previously-unknown landscapes is still possible and incredibly exciting, even now," said Ross.

The Ellsworth Subglacial Highlands charts give scientists a glimpse into ice formation and the history of the West Antarctica Ice Sheet. The researchers collected the radar data by towing ice-penetrating radars via skidoos and small aircraft.  

You can read the full published study detailing the Ellsworth Subglacial Highlands in the January edition of the Geological Society of America Bulletin.