Listen to my chat about Salzburg with Chris Christensen of the Amateur Traveler [here].
German, in its unmatchable flair for creating single, absurdly long, clumsy-to-pronounce words that embody complex concepts, has yet another gem to bestow upon you: sehenswürdigkeiten. If you translate it literally—very literally—it means "seeing-worthy-things," which I prefer to the more figurative translation of "sights of interest." Say it like this: zay-ens-voor-dich-kai-ten (pronounce the "ch" softly, as in the Scottish "loch" or if you can't swing that, give up and say "dish"). You're not going to get the "ü" right, in all probability, but you'll be close. Keep repeating it. Add beer as needed. I find something in the 9-10% ABV range always improves my German.
That's a very long and clumsy introduction to what I feel are Salzburg's most seeing-worthy seeing-worthy-things/sehenswürdigkeiten.
A visit to the fortress complex that sits atop the Festungsberg overlooking the city is a must. It's one of the largest medieval castles in Europe, though it didn't actually see a whole heck of a lot of use—it mostly served as a deterrent to would-be attackers. Construction began in 1077 and continued on through the 16th century. Walk up or take the funicular (you can buy entry tickets that include the funicular or those that don't). Highlights within the citadel include the ornately decorated Golden Hall and the bedchamber of the prince archbishop, which, as your tour guide will inevitably point out, features the radical-for-its-time amenity of an en-suite toilet. Walking the ramparts around the Festung yields sweeping views of the surrounding countryside.
Mirabell Palace and Gardens
Yes, that's the fountain that Julie Andrews and the ersatz Von Trapp children galloped around. If you decide to sing a few bars and skip around, you won't be the first one to do so. Though the gardens look a touch underdeveloped in this photo (shot in mid-March), a visit to Mirabell Gardens is an essential Salzburg experience. To the right of the fountain pictured above, you'll find the curious Zwergelgarten ("Dwarf Garden"), so named because it features a ring of sculptures of ... you guessed it, dwarves. And to the left, Mirabell Palace (Schloß Mirabell), the lovely Baroque bauble of a structure that was built by Prince Archbishop Wolf Dietrich von Raitenau for his mistress, Salome Alt. Actually, the entirety of the grounds was a little "liebesgeschenk" or "love gift," and what a thoughtful sort of dude Wolfie was, at least in this case. Go into the palace (entrance is free) to see what's commonly referred to as "the most beautiful wedding hall in the world," or visit the Orangerie (also free), or just hang out in the beautifully manicured gardens while the sun shines.
On the grounds of the Abbey of St. Peter, you'll find this ornate little cemetery. Is it creepy to walk around cemeteries for amusment? Maybe? My gauge is broken on this one—I like to do it. There are so many decorative grave markers that it's a bit like an open air folk art museum. If your tastes run toward the creepy, get a load of the story behind the markers above: Sebastian Stumpfögger (SUCH a great Austrian name) had the curious and highly suspicious misfortune of being widowed kind of a lot—six times in relatively quick succession. Somehow he found a seventh wife who agreed to marry him (or who had somehow really pissed off her parents), but she escaped his clutches and laid out the case for how Stumpfögger's other wives died with no visible signs of distress: he bound them up in bandages, except their feet—and then tickled them to death.
If you're one of those people who likes to dive into something quotidian in their destination, first, I salute you, because you are my brother/sister. Secondly, and more specifically, let me point you to Salzburg's weekly Schrannenmarkt. This farmer's market, held on Thursdays, is all about regional produce and is not a tourist circus. There are both temporary and permanent (see above) stalls offering all kinds of produce and prepared foods, plus some crafts here and there. It's located right around the Andräkirche, just across the street (Rainerstraße to be exact) from Mirabell Palace. Absolutely one of my favorite slice-of-life activities in Salzburg.
You're going to notice a couple of things about Salzburg: 1. You will hear more about Prince Archbishops than you have ever before heard or believed possible; and 2. There are churches everywhere. From the little ones (try Markuskirche on Ursulinenplatz) to giants (Salzburger Dom, the cathedral), from austere (Kollegienkirche) to ornate (Stiftkirche Sankt Peter), Salzburg is a smorgasbord of ecclesiastical architecture. Make it a personal challenge to see how many you can visit, turn it into a drinking game, whatever. They're beautiful and diverse and rich with centuries of history. Take the Dom alone: the current building sits on the site of what was once the largest Romanesque basilica north of Italy; the prince-archibishop who had this one built overthrew, arrested and locked up until death his predecessor who was also his uncle; and during World War II, a bomb dropped squarely through the main dome of the cathedral. And you thought church was boring.
Climb Every Mountain (Or Like, Two)
The Monchsberg, which wraps around the back of the Altstadt and links up with the Festung-topped Festungsberg, is an easy climb that rewards you with panoramic views of the city, both the near and far side of the Salzach. And it's only a climb in the sense that you have to place one foot in front of the other as you go up some stairs. No grappling hooks or ice cleats needed here, or across the river, where you can clomp your way up the Kapuzinerberg for equally stellar views of the opposite bank. Do 'em both and give yourself a calorie-obliterating excuse for another slice of cake.