Groningen is perfect if you want to combine a city trip with a few days in the countryside. Do the cultural sites on one day and explore the area by bike, pop over to Leeuwarden or walk the mudflats the next.
Groningen was just a small village until the 11th century. After the ramparts were built and later fortified in the 13th century, the village grew into an important trade centre. Unfortunately there's not a lot of the original wall left.
One of the city's most famous attractions is the 100 metre high Martinitoren. This iconic tower is located on Grote Markt (market square) and offers a fantastic view of the city and its surroundings. Another must-do in the city centre is the Noordelijk Scheepvaartmuseum, a real must if you're travelling with children.
Head out towards the German border and visit the village of Bourtange, a replica of the original fort that was built in the 18th century and is still inhabited today.
If you're more into nature, head out to the beautiful National Park Lauwersmeer which has a dike blocking it off from the Wadden Sea. Both are easy to do in one day.
The centre of Groningen is compact making it easy to explore on foot. Public transport or a bicycle - and of course a car - are good ways of doing day trips. The best place to park your car for longer periods are the parking garages in the city centre or the park and ride (P+R) parking lots outside the city. Ask whether your accommodation has parking spaces. Groningen is about 2 hours from Amsterdam and about 3 hours from Hoek van Holland by car. The train takes almost as long and you have to change in Lelystad.
Enjoy this lovely city with interesting sights and more than enough options for great day trips.