Cover art
Harrison, Harry. A Transatlantic Tunnel, Hurrah! Pinnacle/Tor 1981.

Harrison, Harry. A Transatlantic Tunnel, Hurrah! [vt Tunnel Through the Deeps]
Divergence: 1212 CE
What if: Spain remained Islamic after Christian defeat at Navas de Tolosa in 1212, and the War of the Roses fizzled after the early death of Louis XI.
Summary: A 1970s descendant of executed British-American rebel George Washington is in charge of building the ultimate tunnel.
Published: As A Transatlantic Tunnel, Hurrah!, Faber 1972 (0571099963); New English Library 1976; Pinnacle/Tor 1981 (0523485050BUY); Tor 1991 (0812515919BUY), 2010 (0765327864BUY); Gollancz 2000 (0575071346BUY).
Published: As Tunnel Through the Deeps, Putnam's 1972 (0399109188BUY); Berkley 1974 (0425025659BUY).
Published: Originally serialized in Analog, April through June 1972.
Original in: English.
Translation: Nederlands by Rie Neehus as Hoera, een Transatlantische Tunnel, CentriPress 1982 (9030502525).
Translation: German by Tony Westermayr as Der große Tunnel, Goldmann 1973 (3442231787).
Translation: Italian by Luciano Lorenzin as Tunnel negli abissi, Nord 1985 (884290161X).
Translation: Polish by Radoslaw Kot as Tunel transatlantycki. Nareszcie!, Rebis 1997 (8371204787).
Translation: Russian as title unknown, Terra Fantastica 1993 (5792100144).

Harrison, Harry. "Worlds Beside Worlds"
Comments: On writing alternate history and the reasoning behind A Transatlantic Tunnel, Hurrah!, q.v.
Published: In Science Fiction at Large: A Collection of Essays, by Various Hands, About the Interface Between Science Fiction and Reality (ed. Peter Nicholls), Gollancz 1976 (0575021780) and Harper & Row 1976 (0060131985).