"Located at the core of the historical peninsula."
Eminönü is Istanbul's crossroads. Located on the south side of the Golden Horn at the southern end of the Galata Bridge, it's a major transportation nexus for trains, trams, buses and ferries.
Besides transport, it has sights: the Egyptian (Spice) Bazaar, the Yeni Cami (New Mosque), Central Post Office (Merkez Postanesi), Rüstem Pasha Mosque and Sirkeci Station.
It's a major shopping area and has been for centuries. The Byzantines bought their fruits, vegetables and grains here a millennium ago. During the early Ottoman centuries it was the home of a Karaite Jewish colony, who were later moved up the Golden Horn to make way for the building of the Yeni Cami.
You're most likely to use the Eminönü-Zeytinburnu tram and the many ferryboats.