Complex sentence: It is 17.3 km (10.7 mi) long and, unlike the Danube itself, it borders Vienna's city centre, Innere Stadt, where the Wien River ("Wienfluss") flows into it.
Split into simpler sentences: It is 17.3 km (10.7 mi) long. Unlike the Danube itself, the Donaukanal borders Vienna's city centre, Innere Stadt, where the Wien River ("Wienfluss") flows into it.