A little knowledge of the German language can't hurt. Be sure to respect the traffic lights, whether you're a pedestrian or behind the wheel. The country is exceedingly bike-friendly, with rentals available almost everywhere. There is a culture of nudity in some parts of the country; it's most visible in parks and at lakes during the summer, but it also extends to saunas. Almost all stores and supermarkets are closed on Sundays, with some exceptions made on special occasions. Credit cards are not widely used, so it’s best to travel with euros. Drinking in public spaces is normally allowed, but some cities have strong policies against drinking in metro trains and stations.