Shattered glass; broken rocks; boards with nails in them. Walking your dog can be like walking through a field of landmines. Be cognizant of where you are walking. Once my Great Dane and I came across a shattered crackpipe when we were sauntering around a city neighborhood. She could have easily stepped on it and cut her rather large paw. If you're overly concerned about injuries to your dog's paws, you can buy them specially made shoes.