Some weeks ago we visited the "Kamptalwarte" near Langenlois in Lower Austria. A more than 100 years old observation tower that allows a view to all four quarters of Lower Austria.
A really nice hike between 30 minutes and 1,5 hours - depending on what way you choose.
More information in my story: https://www.schmatz.cc/trips/die-kamptalwarte-auf-dem-heiligenstein-bei-zoebing-blick-in-alle-vier-vierteln-niederoesterreichs/