Mystery Flower

I found this mystery flower on a walk in one of the neighborhoods I'm thinking of living in. I would have gotten a closer shot, but rusted barbed wire closed off the area. Any ideas what the pink, flat-petaled flower might be?

(P.S. The beautiful face from yesterday has Japanese parents, but was born in Thailand. But I don't think place of birth is calculated into my friends' who's-from-where guide.)