cargo ship, a barge, cruising on the danube river in stari slankamen, with a panorama of the danube river and its nature in serbia

stari slankamen danube serbia srbija dunav srbiji riverbank river reka vojvodina panorama summer water europe european balkans central eastern navigating nature navigation serbian scenic nautical landscape calm quiet sky forest beauty natural spring sunny barge cargo ship traffic transport industry vessel boat fluvial cruising river one main transportation axis europe's second-longest located europe passing belgrade