Thames Barrier

Traditional dry stone wall, vertical sloping stones, in field in The Burren, County Clare, West of Ireland

Traditional dry stone wall, stones laid flat, in field in The Burren, County Clare, West of Ireland

Traditional dry stone wall in meadow in The Burren, County Clare, West of Ireland

Traditional dry stone wall in meadow in The Burren, County Clare, West of Ireland

Traditional dry stone wall in meadow in The Burren, County Clare, West of Ireland

Eider Barrier on the mouth of River Eider near Toenning - largest German coastal protection building, Schleswig-Holstein, Germany

Construction site, construction of noise protection walls on the A2 motorway near Boenen, North Rhine-Westphalia, Germany, Europe

Construction site on the A59 motorway through Duisburg, North Rhine-Westphalia, Germany, Europe

Tank barrier, defence system Plamort, World War II, to protect Italy from Nazi Germany, near Biotop Plamorter moss, raised bog, at Reschenpass, Vinschgau, South Tyrol, Italy

Construction site on the A59 motorway through Duisburg, North Rhine-Westphalia, Germany, Europe

Bridge at the Estemuendung flood barrage in Hamburg, Germany, Europe

Double yellow line on a street with traffic barriers and 'Road Closed' sign, Connecticut, United States of America

Safety cones lined up across a rural road, Saskatchewan canada

Man in wheelchair holding caution tape

barriers on roadway