On flights home from Europe, we’re usually already planning our next trip. It took a long time to get to Greece, being that much farther from parts of Europe closer to the USA, but with our upcoming trip to Crete, we’ll have been there twice in 2 years!
Italy's a long country, running north and south, and it’s different, in climate, sights, and lifestyle, depending where you are. The far north is mountainous, and parts of it were once part of Austria, ceded over after World War I. Rome can take a week or more of your itinerary, especially with its wealth of museums and ancient sights. Other places are worth a visit, north, south, and in between. There’s also Sicily, way south.
Austria, running east-west, may be a little more culturally similar throughout the country, but the alps are in the west and Vienna is to the east. Austria's got some fine wine, too, mostly white. And a tour of a salt mine should be on everyone’s bucket list.