Mariam Amash, who lives in the village of Jisr a-Zarka in Israel, claims that she is 120 years old. Her claim recently surfaced when she applied for a new Israeli identity card.
She might be telling the truth. Apparently she has a birth certificate issued by Turkish authorities, who ruled Jisr a-Zarka back in 1888 when Amash says she was born. She also has eleven children, the eldest one being in her late 80s. So assuming that her children aren't lying about their ages, Amash would have to be at least over 100 years old.
If Amash really is 120, that would make her the oldest person in the world. According to the Guinness Book of Records, the current record holder is 114-year-old Edna Parker of Indiana.
The reason to be skeptical about her claim is because of the phenomenon of age exaggeration. Elderly people often lie about their age, pretending to be older than they really are. They usually do this because claiming extreme age is a way to gain social status. In Amash's case, it seems kind of odd that she would have eleven children, if she only had her first child when she was in her mid 30s (which the age difference between her and her oldest daughter suggests).
Researchers have been fooled by the age exaggeration phenomenon before. The most famous case occurred in the Ecuadorian town of Vilcabamba, located high in the Andes. The town gained fame during the 1970s because it appeared to be the home of 23 centenarians, which statistically was unheard of. Even one centenarian among a population that small would have been extraordinary. It turned out that basically all the elderly people in the village were lying about their ages. When researchers carefully examined the birth records, they realized there wasn't a single person over 100 in the village. The average age of the people claiming to be over 100 was 86. The plans to build a longevity research center in the village had to be scrapped.