Chris Rowan tweeted about this interesting structure in the Democratic Republic of Congo, revealed through deforestation. I went onto Google Earth to find it, and found it located at  3°42'22.84"S, 24°32'10.74"E.
The Unia River is apparently controlled here by the ring-shaped structure of a putative crater, imparted by a bolide impact. I am reminded of Lockwood’s posting of Manicouagan Crater, Quebec.
So there is a positive side to deforestation after all…