Markers are indicators on google map to denote the places of interest. This post will explain you how to place a marker on google map.
The marker object resides in the google.maps.Marker namespace and takes a single argument, options. Options is an object literal called Marker options that can have several properties of which two are required:
Map is a reference to the map where you want to add the marker.
This property indicates the position of the marker and is of type google.maps.LatLng