Yes,they are real.
These Chinese characters are political slogans.
30 or 40 years ago,soldiery used stone and cement to create
these slogans.Not crop!
But artfully,these slogans are navigation marks.
4233'6.31"N, 9413'6.95"E is an military airfield,these slogans
can help pilots piloting plane.
Every Chinese character is as long(and wide) as more than 50m!!!