The architecture of Mykonos is characterized by the blue color of the sea and the white of the light. Τhe houses were built by the inhabitants so that pirates could not easily approach them. The houses are in the shape of a cube without roofs, one next to the other and they are separated by narrow alleys. The buildings of the Cycladic island are distinguished by asymmetrical and rounded corners. Various eras are found in architecture. The classic and the island element coexist. Most of the houses are connected by external stairs and are two stories. There are listed buildings, which function as museums and exhibition spaces. One can walk through the alleys of the island and enjoy the different architectural styles and the bougainvillea that flood the alleys of Mykonos. On the island of Mykonos there are several monuments, each of which refers to another era. The most notable are the Mycenaean Vaulted Tomb and the ruins of the prehistoric proto-Cycladic acropolis, in ancient times the towers and in the Venetian rule the "little Venice", but also the well-preserved chapels from the 17th and 19th centuries. Also impressive are the windmills of Mykonos that once ground the grain of the inhabitants, sustaining the island's economy. In addition, there are several lighthouses and wells on the island. The Three Wells is one of the most characteristic examples, as they supplied the island with water until the middle of the 20th century.