Ils ne passeront pas!

Ils ne passeront pas! They shall not pass,  is a slogan used to express determination to defend a position against an enemy. 

It was most famously used during the Battle of Verdun in the First World War by French General Robert Nivelle. 

These are the remains of concrete anti-tank blocks built on Newburgh beach in 1940 when we were living in fear of being invaded by Nazi Germany. Thankfully, they were never put to the test.