Megalithic monuments in Britain are mainly concentrated in western and northern areas where sources of suitable stone were widely available. In the south and east of the country comparable monuments were mainly built of wood. Many different styles exist, some reflecting local traditions while others illustrate changing preferences over time. Strong connections can be seen in the design of the monuments with structures south-westwards along the Atlantic seaways in Ireland, France, Spain, and Portugal, and eastwards towards southern Scandinavia, northern Germany, and the Netherlands.