There's a Elevation Sign located at the Heiner Metzger Place in Neu-Ulm, Bayern, Germany.
This is an official German geodetic reference point and at this place, you can check your GPS device with regard to the coordinates and the altitude.
The public and accessible checkpoint were mounted exactly. Using these control points, the accuracy of GNSS receivers can be verified. Given by the GNSS receiver is placed on the corresponding mark of the control point and comparing the measured coordinates with the reference coordinates specified at the checkpoint. The coordinates are specified where in addition the Gauss-Krüger or UTM coordinate system of the respective meridian strip both in the WGS-84, and ETRS89-.