The Pillboxes of Lanazarote

In 1940 General Franco contemplated supporting German operation Felix: the capture of Gibraltar. Since he feared a British reaction towards the Canaries, he ordered the construction of defences. Because of this Lanzarote has many bunkers. Luckily for Spain, Franco stayed neutral.
In 1941 Hitler offered Anti-Aircraftguns and Stukas to be stationed on the islands. However, the German Operation Barbarossa and contrasts between Hitler and Franco caused Gibraltar to remain British and no Allied invasion of the Canaries.
The British knew of the German/Spanish plan to invade Gibraltar (operation Felix). Operation Pilgrim was a preemptive invasion to prevent German control of the Canary islands. The German invasion never materialised and consequently, Operation Pilgrim was never put into action.
Lanzarote coastal artillery comprised 3 x 107 mm Arisaka and 4 x 152 mm Putilov guns. These were Russian guns, sent by the USSR to the People's Republican Army during the Spanish Civil War. After the war they passed to the Spanish Army.
On Lanzarote 75 bunkers were built, next to 56 machine gun nests and 5 artillery casemates. The pillboxes were of a simple design, easy and rapid to built. Local magmatic stones provided camouflage and reinfored the pill box structure.