On a page styled with Twitter Bootstrap and using the navbar I wanted to fill the whole container below the navigation bar with a Google Maps map. To accomplish that I
You could solve the problem with absolute positioning.
.fill { top: 40px; left: 0; right: 0; bottom: 0; position: absolute; width: auto; height: auto; }
Demo (jsfiddle)
You could also make the navbar .navbar-fixed-top and somehow add a padding or margin inside the #map element.
.navbar-fixed-top
#map