Anna-Tower, Observation tower in Springe, Germany.

The Anna-Tower is a 28-metre concrete observation tower on the Bröhn, the 405-metre summit of the Deister ridge in the Calenberger Bergland. A spiral staircase of 116 steps leads up inside the tube to a viewing platform at 433 metres above sea level. A forest restaurant, the Waldgaststätte Annaturm, is attached to the tower.

A wooden tower was built on the Bröhn in 1833–34 for Carl Friedrich Gauss's land survey, with the measuring point Deister II; his son Joseph Gauss and G. W. Müller carried out the work. Ernst Brauns erected a wooden lookout here in 1879 for the Hannoverscher Bürgerverein and named it after his wife Anna. In 1904 the Hannoverscher Touristenverein replaced it with a green-painted iron structure costing 5,000 marks. The sixth tower, a concrete tube built in 1982 and financed by the Großraumverband Hannover, stands today.

The tower's name comes from Anna, the wife of Ernst Brauns, who built a wooden lookout here in 1879 for the Hannoverscher Bürgerverein. The hut at its foot, opened in May 1932, was named Ernst-Söhlmann-Hütte after the long-serving chairman of the Touristen-Verein. A Gaußstein on the restaurant terrace recalls the surveying point Deister II set up in 1833–34.

The tower is reachable via hiking trails that connect to nearby parking and public transportation. Bring sturdy footwear and check the weather before you go, as conditions can change quickly at higher elevations.

The tower's predecessor was demolished in 1978 as unsafe; its foundations still lie in the beer garden a few metres west of the 1982 replacement. The current tower is the sixth on the Bröhn summit, and a Gauss stone on the restaurant terrace recalls the 1833–34 survey tower.