The village Großmugl ("big mound") is named after this big tumulus. The so called Leeberg is a listed archaeological burial site. The tumulus is still 14 m high and reaches about 50 m in diameter. Nearby is another, smaller tumulus, which was excavated in the 1950s. Although a lot of ceramics were found the scientific outcome wasn't satisfying. The big Leeberg itself will remain untouched, until it will be necessary to dig it up.
Keeping something impressive and almost unique like that as save as possible is more important, instead of destroying it by digging it up. Leeberg is a perfect photo model, because it is well visible situated on top of hill, high above the village. It is also visible from the other side of the village too.
Such gigantic burial mounds were built during Early Iron Age (Hallstatt Culture 8th to 6th century BC). The Leeberg of Großmugl is a very prominent and good visible archaeological site, but it’s not the largest tumuli in Austria. It's just a large and good visible example. Never fully believe in Wikipedia or schoolbooks!
In Burgenland, eastern Part of Austria, nearby the Hungarian border is a large burial ground with more than 280 tumuli. Some of them even larger than the more famous Leeberg. Because this large burial site was never used for farming and was almost forever overgrown by trees the tumuli are in far better condition than this big "lonely mountains" in the middle of farm land in Lower Austria. Some of them are so well preserved, that the ditch around the tumulus, were the earth was taken, to built the grave, is still visible. Another one of them is half finished. It looks like a round "step pyramid".
Sadly some of them were opened by bored noble families of the region during the late 19th century. They look like slaughtered giants.
During WWII defense systems for big weapons and trenches for the soldiers were built right through the burial site. If treasure searching idiots try to dig in this area, they will doing it on very dangerous ground. Although bomb squads cleared the area, there will be still enough dangerous bits and pieces of WWII left. At least my brother-in-law, he was the assigned archaeologist of Burgenland, and I found enough dangerous stuff during a rescue excavation. It's never funny to find ammunition, grenades or bombs – at least I’m not very fond about finding such remains and calling in the bomb squad.
It's almost impossible to take pictures of this more preserved but hidden graves. If you step back, the trees will hide the tumulus. If you step forward, nothing but rotting leaves and twigs will be in the pictures.