The city in which Leonardo da Vinci produced 'Mona Lisa' a famous painting in history?

Leonardo da vinci began painting The Mona Lisa in 1503 or 1504 in Florence, Italy. According to Leonardo's contemporary, Giorgio Vasari, "...after he had lingered over it four years, left it unfinished...." Leonardo, later in his life, is said to have regretted "never having completed a single work".