Belvedere Palace was a quick stop for us but in my mind, still worth the short stop for pictures, especially if you can go before the crowds hit (we arrived in the morning and there was nobody there, by the time we were about finished with photos, tour groups arrived). While we didn't actually go inside the two palaces themselves (called Upper Belvedere and Lower Belvedere), the grounds are open to public and there was no admission cost when we went in 2015.
Construction started in 1712 and both the upper and lower palaces were completed in 1723. It was built for Prince Eugene of Savoy as his summer palace by architect Johann Lukas von Hildebrandt. Now, both palaces are art museums and feature many Austrian paintings.
It is very easy to access Belvedere by public transportation, by Tram, stop at 'Schloss Belvedere' which is how we got here. You can also take the metro as well.
For more information, visit their official website at: https://www.belvedere.at/en
Come back next Friday for another Past Point of Interest!