On the northeastern coast of the island, at the Maroulas area near Loutra, archaeological excavations brought to light very significant findings related to human evolution in the Eastern Mediterranean basin. The excavations, which ended in 2005, unearthed 30 round spaces that used to be hut floors. 15 tombs, one of which contained a human skeleton and grave goods made of pyrite, obsidian, and quartz, were found below their stone layers. Ten different carbon samples were used to define the age of the findings that lies somewhere between 8800 and 8600 BC. Clearly, Maroulas of Kythnos has an outstanding position on the world map of paleoanthropology, as this is the first time that an outdoor area with built structures from the Mesolithic period is discovered in Greece, and more specifically in the Aegean area. The settlement was either built at the same or at an earlier period than the one in the cave of Frahthi in Argolida and the one in the cave of Gioura on Alonnisos. The Mesolithic era, that is the one that separates the Palaeolithic from the Neolithic era, constitutes a transitional stage for humanity between the nomadic hunter-gatherer society and the permanent settlement and development of agriculture and fishing. Maroulas and its proximity to Milos, from which the necessary obsidian stone was obtained, prove the active role of the Cyclades in the evolution of the early prehistoric man.