The village of Costi is also situated in a picturesque valley of the river Veleka and it is 25 km to the southwest from the town of Tzarevo. Disputable are the hypothesizes concerning the origin of its name. Some sources consider that it comes from the fire-dancing holiday "St. St. Constantine and Helena" that is honored here but other thought it bears the name of the Greek wealthy man – Costakis. Probably the two versions are somewhat right because Costi is one of the most famous with the fire-dancing villages, where till today hereditary fire-dancers
are playing over growing embers during the fairs. Like the village of Brodilovo here also has lived Greek population till 1914 whose houses mould today its unique appearance. The church "St. St. Cyril and Metody " was ruined during the revival uprising and was restored again in 1909 an the most remarkable in it are the woodcarving iconostasis and many restored icons. It is declared also as a architectural monument. Across Costi was passing the old road from Malko Tarnovo to Vasiliko (nowadays Tzarevo) and Ahtopol that was with great economical and commercial significance.