This example make use of the most detailed map of the "Game of Thrones" world ever

You can find more info about the map in the site http://www.sermountaingoat.co.uk/map/index.php

This is an excerpt of the code used by the sample

    @(Html.GoogleMap()
        .Name("map")
        .Zoom(1)
        .Height(520)
        .Latitude(0)
        .Longitude(0)
        .ZoomControlStyle(ZoomControlStyle.Large)
        .StreetViewControlVisible(false)
        .ImageMapTypes(map =>
            map.Add()
                .TileUrlPattern("~/maptype/GetLabeledTile?x={0}&y={1}&zoom={2}&tileWith={3}&tileHeigth={4}")
                .TileSize(new Size(256, 256))
                .RepeatHorizontally(false)
                .RepeatVertically(false)
                .MaxZoom(4)
                .MinZoom(1)
                .MapTypeName("Labels")
                .MapTypeAltName("Game of Thrones Labeled")
        )
        .MapTypeId("Labels")
     
)

Notice that the TileUrlPattern could be whatever url that returns a tileImage.
Be aware that the TileUrlPattern value will be parsed by the control to find and replace the string parameters in the following order

0. x
1. y
2. zoom
3. tileWith
4. tileHeigth