What Causes Vaginal Bleeding After Menopause?

63 years of age extremely healthy, muscular, farm girl, 2 ten pound baby boys. went in to menopause about 10 years ago. Today started vaginal bleeding just like a period. No pain, no itching, never had yeast infections. When I had a period it was like a river, had to use (2) tampons to slow down the flow for the pad. Was like that from age 13 to 55 when I just stopped. No hot flashes, no pain, no mood swings. Strong and healthy. I have never had the flu, never been sick, have checked out ok for colon cancer, am checked every 5 years. Had a total of 3 benine polups removed at different times. Woke up this morning wiped and low and behold blood. Smells like menstrual bleeding. No pain, no cramps, just gentle bleeding.