Bourtzi or "the Castle» by the Venetians , or " Thalassopyrgos " in the 1821 race , is a small island in front of the port of Nafplion .Small boats head out to the fortress, leaving from the port fairly regularly. The trip lasts only a couple of minutes, and the view towards the city is at its best just before sunset. Entrance: Free, boat trip 4, 5 Euros per person .