Why do certain property in Japan had roof covers placed on top of their fences?

Question:

I've seen some houses in Japan which installed roof covers on top of their concrete/bamboo fences. Furthermore, on certain properties even the fence entrance itself had an unbelievably large roof built on top of it.

Does the roof serve a specific purpose/cultural reasons, or was it built purely for its aesthetic looks?

Honestly, I think they are very beautiful and exotic.

Answer:

Are you talking about walls as seen in the pictures below?
If these are what you are talking about, yes it's built for aesthetic looks, reducing weather stain, and protecting from erosion.

http://ameblo.jp/shogakuji/image-1047484…
http://blog-imgs-27.fc2.com/o/k/u/okurom…
http://matsui.dip.jp/bike/tsukuba-mounta…
http://eiruc.cocolog-nifty.com/photos/un…
http://osharenayane.blog.so-net.ne.jp/_i…
http://blog-imgs-47.fc2.com/m/i/t/mitobe…

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EDIT
sorry, I really don't know how it is called officially/specifically. maybe "屋根塀 yanebei" ? That said, I'm not sure how many Japanese ppl could picture it when asked, "do you know "屋根塀 yanebei"?
I guess, most of Japanese ppl would simply say, "that is a wall/fence with a roof cover on top of it."