The river Amstel is a broad river meandering through the city, to whom Amsterdam owes its name. Most old cities in Europe have such a river like the Thames in London and the Seine in Paris. People settled a city along a river due to the transport posibilities by boats. There are nine bridges over the river Amstel, this is a new one from 1970 called the Toronto bridge due to the two twinned towns.
This is one of the old bridges the "Hogesluis" dating from 1883. It is decorated with city arms.
Looking from above bridge you can see the Skinny Bridge from 1934 with the Townhall in the background.
Here an air photo from internet with the river Amstel
and the bridges.