The name is used to refer to 21 people, mostly from Werkendam, who during the last months of the war maintained a secret connection between occupied and liberated Netherlands across the Biesbosch and the Merwede.
One of the people who crossed was the British general John Hackett who had been wounded during Operation Market Garden.
During the end of the war, after Dolle Dinsdag, several German troops deserted, mostly across "the bridge of saint Jan".
The following agents crossed from occupied into liberated territory: On Tuesday 4 December 1984 about 50 people of the Biesbosch resistance group meet.
There are several monuments dedicated to the Line-crossers, most prominently in Werkendam,[3][4] Hank, Lage Zwaluwe[5] and Sliedrecht.