evidence: They share a complicated relationship marked by differences in religion, politics, culture, and a variety of bilateral issues. With 241 kilometers of common border, the two states have multiple border disputes, namely around the Danube river and the islands of Šarengrad and Vukovar. Croatian and Serbian, official in Croatia and Serbia respectively, are mutually intelligible standard varieties of the Serbo-Croatian language. Between the two states, 186,633 Serbs live in Croatia with 57,900 Croats living in Serbia (as of 2011).[1][2] [...] Border dispute [edit]Due to the meandering of the Danube, the eastern border of Baranya with Serbia according to cadastral delineation is not followed, as each country controls territory on their side of the main river flow. Further south, near Vukovar and near Šarengrad, there are two river islands (Island of Vukovar and Island of Šarengrad) which have been part of SR Croatia (during Yugoslavia) but during the war they came under Serbian control. [...] - ^ "Čija je Šarengradska ada?". rts.rs (in Serbian). Radio Television of Serbia. 7 February 2010. Retrieved 4 January 2013.