victory over the Serbian rulers Vukašin Mrnjavčević and Jovan Uglješa, who died in the battle. Migration The Maritsa river as a natural barrier on the border between Turkey and Greece has become a major route for migrants from a variety of countries attempting to enter the EU irregularly. Between 2000 and 2019, 398 bodies were found on the Greek side of the Maritsa river. Up until that time, drowning in the Maritsa was the leading cause of death among migrants trying to enter Greece. Following the heavy losses Turkish armed forces incurred at the hands of the Russian-backed Syrian government in northern Syria at the end of February 2020, a drastic change in Turkey's policy towards irregular migrants on its territory led to escalation of the situation at the Evros border crossings as well as exacerbation of tension between Turkey on one hand and Greece and the EU as a whole on the other hand. In May 2020, news emerged that Turkish forces occupied a of Greek territory, Melissokomeio, as shown on maps of 1923, following a change in the flow of the Maritsa river. Tributaries Starting from the river's source, significant tributaries of Maritsa include: Left tributaries: Topolnitsa (flows into Maritsa near Pazardzhik) Luda Yana (near Ognyanovo) Stryama (near Sadovo) Sazliyka (near Simeonovgrad) Tundzha/Tunca (in Edirne) Ergene (near İpsala) Right tributaries: Chepinska reka (near Septemvri) Vacha (near Stamboliyski) Chepelarska reka (near Sadovo) Harmanliyska reka (near Harmanli) Arda/Ardas (near Edirne) Erythropotamos/Luda reka (near Didymoteicho) Floods The lower course of the river Maritsa, where it forms the border of Greece and Turkey, is very vulnerable to flooding. For about 4 months every year, the low lands around the river are flooded. This causes significant economic damage (loss of agricultural production and damage to infrastructure), which is estimated at several hundreds million Euro. Recent large floods took place in 2006, 2007, 2014, with the largest flood taking place in 2021. Several causes have been proposed: more rainfall due to climate change, deforestation in the Bulgarian part of the catchment area, increased land use in the flood plains and difficult communication between the three countries. Honours Maritsa Peak on Livingston Island in the South Shetland Islands, Antarctica is named after Maritsa River. La Maritza is also a 1968 song written by Jean Renard and Pierre Delanoë and interpreted by Sylvie Vartan. Hebrus Valles on Mars is named after this river. The Bulgarian Maritsa