The 265 metres high Vajont dam in the Carnic Prealps (completed in 1959) was at that time the tallest dam in the world.
On 9th October 1963, a huge landslide from Monte Toc rapidly fell into the partially filled lake. 266 million cubic meters of rock lid into the Vajont reservoir. It displaced about 50 million cubic meters of water, that poured down into the valley. An enormous wave completely destroyed the village of Longarone and others causing estimaded 2000 deaths. The Vajont dam still exists, but the reservoir itself is now empty beyond the natural level of the lake.
The image of the stamp looks identic with pictures before the disaster. There is also depicted the church tower of Pirago (today part of Longarone), surprisingly survived while the rest of the church and the whole village were swept away by the violent wave of water.
The two mountains in the background are Monte Cornetto (left/1'899 m) and Monte Zerten (middle/1'883 m). At the right the foothills of Monte Toc (1'921 m).