The Limes used to run over the Gaulskopf, on which the Roman watchtower WP 4/16 (numbering of the Reich Limes Commission) was located. Standing on the summit, the tower offered a panoramic view of the surrounding Taunus heights of the eastern Hintertaunus and the Wetterau. The watchtower on the Johannisberg provided a visual connection to the Friedberg fort. Similar towers, which probably belonged to a signal chain, were located near Wölfersheim-Wohnbach and on the Kapellenberg near Hofheim am Taunus. The tower on the Gaulskopf was located between the small fort Kaisergrube and the small fort "Am Eichkopf" (see list of forts on the Upper Germanic-Raetian Limes). Today, the Limes Adventure Trail Hochtaunus follows the course of the Limes over the Gaulskopf.[4]
In 1926, the current reconstruction of the Roman tower was inaugurated. Only ruins of the original tower remained. The reconstruction was carried out with funds from Gustav Oberlaender (June 2, 1867 to November 30, 1936), a German-born hosiery entrepreneur from the USA. The 15.1 m[5] high tower is unusually large with a side length of 8 m. A total of 47 steps lead over an intermediate floor to the enclosed observation platform at a height of 8.8 m, which allows a view of the surrounding area through 16 arched windows.