Turtledove, Harry. "Down in the Bottomlands"
Divergence: c 5,500,000 BCE
What if: The Mediterranean basin never opened to the ocean.
Summary: In modern days, a murder during a tour of the Bottomlands Trench reveals a plot to destroy the "Gibraltar" mountains with a nuclear weapon.
Published: In Analog, January 1993; The New Hugo Winners, Volume IV (ed. Gregory Benford), Baen 1997 (0671878522BUY); Down in the Bottomlands and Other Places (with L. Sprague de Camp), Baen 1999 (0671578359BUY); amd We Install: And Other Stories, Open Road Media 2015 (1504009428BUY).
Original in: English.
Translation: Italian by Enzo Verrengia as "Laggiù nelle Terrefonde", in Isaac Asimov SF Magazine [[date unknown]]; Analog Fantascienza 3, Phoenix Enterprise 1995; I Premi Hugo: 1991-1994 (ed. Piergiorgio Nicolazzini), Nord 1995.
Translation: Spanish by Claudia de Bella as "En las tierras del fondo", in Axxón #66.
Awards: Winner: 1994 Hugo for best novella.