Well a lot of people have asked about the various anti landing devices and here are a couple.
Jurre Lagerwaard was kind enough to point out that these below are Czech Hedgehogs.
...and I think these are a Tobruk pit and a Goliath
Gordon Rottman tells us what a Tobruk pit is: A Tobruk pit is a small concrete fortification that is completely underground. Essentially it is a foxhole with its exposed portion flush with the ground. The opening, or fighting position, lacks overhead cover. The underground portion consists of a small troop shelter and ammo storage. Usually it was used as a machine gun position, but versions existed for 5-cm mortars and on the Atlantic Wall a slightly enlarged version existed on which a French Renault light tank turret was fitted. The original Tobruk pits were of course developed at its namesake local and consisted of a foxhole with an attached underground dugout to protect from artillery. There was no berm or parapet around the foxhole. It was completely flush with the ground making it very difficult to detect from ground-level. It may have been developed by the Italians as they had long used bermless fighting positions in the desert.