The park was designed by the French bureau Agence Ter (https://agenceter.com/project/aqua-magica/), especially for the horticultural exhibition of 2000, it is one of the newest parks in North Rhine-Westphalia. There are good playgrounds for children and various water features.
The centrepiece of the park is the Wasserkrater geyser, which is unique in Germany. Water bursts out from a depth of 18 metres to a height of 30 metres. You can watch this action from above or from below, risking to get wet.
Interestingly, the water rises up by force of nature, as the salt water is under high pressure underground.
The park is open all year round from 9am to dark, and the geyser is open from late April to early October. Thursday and Friday from 11am to 6pm, every 30 minutes, Saturday and Sunday from 10am to 7pm, every 20 minutes. The ticket is 2 euros.
Getting there: car park 52.195694, 8.783389. There are two railway stations: Bad Oeynhausen or Bad Oeynhausen Süd.