Großer Stein, Glacial erratic in Altentreptow, Germany.

Großer Stein is a granite boulder in Altentreptow with measurements of 8.2 meters long, 6 meters wide, and 5.2 meters tall. Its rough surface texture and substantial size make it a striking feature in the flat surrounding landscape.

The Große Stein was probably transported to its present site during the Weichselian glaciation. In 1832 the geologist Ritzky mentioned it in the Baltische Studien as one of northern Germany's most notable glacial erratics. Around 1900 it appeared frequently on postcards; later it was called the Bismarck-Stein, and in 1915 a Bismarck relief and inscription were unveiled. In November 1959 the Ministry for State Security ordered the relief removed; traces of that removal remain visible on the front. In 2021 the town lifted the stone about three metres with hydraulic presses at a cost of 244,000 euros, a measure criticized by the Bund der Steuerzahler.

A local legend says the devil, or a giant, threw the stone in anger at Altentreptow's church tower, missed, and it landed on the Klosterberg. Around 1900 the boulder appeared often on postcards, and from 1915 it bore a Bismarck relief with the inscription "Bismarck 1. April 1815 1. April 1915"; the relief was removed in November 1959 on orders of the Ministry for State Security, and traces of its removal remain visible on the front.

The stone is easy to reach and can be viewed from all sides, as it was lifted from its partially buried position in 2021. Visitors can examine the complete exterior shape and surface features of the granite formation up close.

The 2021 lifting revealed the stone is about 20 m³ larger and 65 tonnes heavier than previously estimated, bringing it to 166 m³ and 450 tonnes. Samples from the ton-heavy splinters found in the excavation pit cast doubt on the earlier assumption of Hammer granite from Bornholm and instead point to an origin in Sweden.