It is the narrowest and, with 113 metres (371 ft), the deepest, section of the Dardanelles Strait. As a result, it is also the point where the surface current from the Black Sea to the Aegean Sea is the strongest, with 1.5 to 2 times the normal rate, occasionally reaching the speed of 5 nautical miles (9.3 km) per hour. The undercurrent is 0.5–5 nautical miles (0.93–9.26 km) per hour, flowing in the opposite direction.[5][6] The ancient and medieval city of Abydos is located at the Nara promontory.[7]
Due to the narrowness of the straits at this point, the site was often chosen for crossings of the Dardanelles by armies, beginning with the Achaemenid monarch Xerxes I during his Invasion of Greece in 480 BC, who deployed pontoon bridges to allow his army to cross on foot.[7]
^Ünlülata Ü.; Oğuz T.; Latif M.A.; Özsoy E. "On the Physical Oceanography of the Turkish Straits". In Pratt L.J. (ed.). The Physical Oceanography of Sea Straits. NATO ASI Series (Mathematical and Physical Sciences). Vol. 318. Dordrecht: Springer. p. 32.
^Oceanography of the Turkish Straits - Volume 2, Issue 1 - Page 2-9, 1988. "The first two stations cover the northeastern part of the Strait from its Marmara end (Gelibolu-Çardak section) to the vicinity of the Nara Burnu where the channel is constricted and bends sharply. The profiles of the hydrographic properties are ..."