The massive Fort that runs round the settlement like a girdle, dates back to 1559 AD. The Colossal structure in the present form encompasses about 30,000 sq. Meters. with 10 bastions and two gateways. The Fort is protected by a moat on the land side and also connects the river to the sea. It is basically polygonal in plan with projections at regular intervals of about 500 feet and carrying splayed angular bastions.

        The parapet above the fortification walls is without merlons but is provided with loop holes. The terraces close to the top of the wall are connected to the top of the wall are connected to the inner ground surface by open flight of steps at many places. All along the inner wall, there are barracks for defense personnel's. The inscription above the southern (land) gate mentions that this gate along with the bastions adjacent to it was completed in 1581 AD. after the Mughal invasion in Akbar's reign. The inscription on the Northern (sea) gate gives the date of 1593 AD. for the completion of the Fort wall. On the Northern side within the confine of the Fort were located the palaces, the Secretariat and other official buildings. A large number of Portuguese gentry and their families resided within the Fort.

        The small fort with high stone walls encloses an area of 12,250 sq. meters. It has three bastions and two gateways.

        The most conspicuous part of the Fort is the giant gateway facing the river with a large statue of St. Jerome and two giant human figures, on either side of the gateway.

        The imposing church of Our Lady of the Sea is the principal building within the Fort.

        Nani Daman offers some wonderful sites to the traveler : Gandhi Park near Nani Daman jetty, Nani Daman Fort and the church inside and the fishing jetty where boats are anchored to name a few. The tourist crosses over to Moti Daman through the Daman - Ganga Bridge where an old world of broad roads, the massive Fort, the stately Light house, Gardens, Historic Monuments and ancient Churches in Gothic style provide a feast to the aesthetic taste.