Perhaps part of a bunker??
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I'd guess the first photo was taken somewhere besides Japan, perhaps the Philippines. Why? The palm trees.
The second photo is Okinawa or somewhere close. That is a traditional Okinawan tomb. The Japanese used them as bunkers and storage sights during the war, and American Marines and Soldiers had to check each one just in case. And Palm trees are all over in Okinawa. It is more of a northern tropical island.