The tower was built on the ledge of the coastal rock and consists of a cylinder 28 m in height and 16,5 m in diameter which was inlaid with local grey limestone. The thickness of the walls at the foundation is 5 metres, and in the upper part 4 metres. On the eastern side a projection, the purpose of which is still unknown joins the tower. The internal space of the tower is divided into 8 tiers which can shelter more than 200 people simultaneously. Each of the eight tiers of the tower is covered with a stone cupola with a round opening. The light penetrated inside through the narrow window openings of a loop-hole type, widening inwards. The communication among the tiers was carried out with the help of the winding stone staircase, laid in the thickness of the wall. The first tier, like in other Apsheron towers was connected with the second one through an attached or rope-ladder, which could be taken away in case of danger. Bays are constructed in the same thickness with the walls, inside them are laid a pottery pipe 30cm in diameter. There is a well 21m deep inside the tower, cut in the rock to the water-bearing stratum from the third tier. The water here was clean and fresh.

The construction date of the Maiden Tower has not been fixed yet. Often its construction is ascribed to the XII century. This is the age of the plate with the inscription laid from the outside of the tower.

    

It is also rather hard to define the primary functional purpose of the Maiden Tower. The original construction of the tower as a defence structure gives rise to doubt. It is of little use for a defence because of the small area and the lack of the conditions for a long stay. The existing narrow window openings are directed towards the sea and is not intended to repulse the attack of the enemy. Though it is somehow possible to defend oneself from the enemy only from the top of the tower. Besides, it has been calculated that it could be possible to build another wall around the city with the stones and lime spent on the construction of the tower. There are versions that primarily the tower was constructed as a temple of fire (the word "Gala”- "tower” has another meaning in Azerbaijani – "to light a fire”), a Zoroastrian hut (that is the tower, where on the top were laid the bodies of the people for the black kites to tear to pieces), an observation point. But it is doubtless that in the XII century this splendid tower was part of the defence system of Baku and was the main citadel of the Baku fortress, one of the most powerful fortresses of the Shirvanshahs. In the XVIII-XIX centuries the Maiden Tower was used as a beacon. The beacon in the tower began to give light since June 13, 1858 but until then a fortress flag had been hoisted on it.

The tower has repeatedly been restored. The tower was last restored in the 1960s. In 1964 the Maiden Tower became a museum, and since 2000 has been included in the UNESCO list of the monuments.