The romantic little town of Valkenburg lies in the picturesque Geul valley, in the Limburg uplands, below the only hilltop castle in the Netherlands. It has long been a very popular holiday resort. A hundred years ago its main tourist attractions were its caves: it now also attracts visitors with its spa facilities in the futuristic Thermae 2000
, one of the largest spa establishment in the Netherlands after Nieuweschans in Groningen. Valkenburg also has the country's oldest functioning railroad station (1853).