I understand the name of this huge monument by Ferit Özşen at the Kordon on a square called Gündoğdu Meydanı (Sunrise - or The sun has risen - Square) in the Alsancak area is Tree of the Republic, it commemorates the 80th anniversary of Turkey becoming a republic.

From the Turkish Wikipedia I gathered: Cumhuriyet Ağacı / The Tree of the Republic, consists of an 8.5 m high marble-covered base and a copper sculpture depicting ten horsemen placed on this base. On the base of the monument, which has a total length of 13.5 meters, there are reliefs and inscriptions describing the Hittite, Seljuk and Ottoman civilizations and the foundation of the republic. The statue, symbolizing the National Struggle , was placed facing west in order to receive better light. The faces of the horsemen depicted in the statue are unclear and do not wear military or civilian clothing.