One of Hanoi's most noticeable characteristics is its many ponds and lakes. Even short-term visitors will take a look at the more centrally located bodies of water, like Hoan Kiem Lake, West Lake and its subsidiary Truc Bach and perhaps Thien Quang and Bay Mau Lakes just beyond the French Quarter. But the city has many kore, plus a multitude of nameless ponds, while long dikes have been keeping the city protected against potential Red River flooding since ancient times. Within its designated urban boundaries Hanoi has more water than any city east of Venice.