I came to this site by chance. I see it uses Google Maps, but what they did to the map will be displayed in such a way? (No icons course)
2 Answers
The custom map tiles are achieved via Styled Maps. Check out the API reference to see what can be customized and to what level.
as per @Andre said, it is styled.
If you want to play around with the style , you can try it here : FlatUIMaps. You can download the configuration in json format after changing the layer.