Tzoumerka,Greece. The historic stone bridge of Plaka in Arta, western Greece has been standing over Arachthos river for 148 years. It was the biggest one-stringer bridge in the Balkans. It was constructed by Constantinos Bekas in 1866.It is the widest stone-made bridge of Epirus and probably of Greece. The bridge of Plaka, is considered as the biggest single-arch bridge in the Balkans, with 40m arch span and 21m height.