What's the must-see thing in Krakow?

Rynek Główny is 40,000 square metres of open cobblestone, the largest medieval market square in Europe, planned in a single royal charter in 1257. Most visitors drift in from Floriańska Street and stop when the space opens up. That reaction is correct. The Cloth Hall runs down the centre, and its ground-floor stalls still sell amber and hand-carved chess sets the way vendors have since the Renaissance. At the northeast corner, St. Mary's Basilica rises 80 metres. Walk inside and look up. Veit Stoss carved the wooden altarpiece between 1477 and 1489, and it stands 13 metres tall. The faces on the carved apostles still carry individual expressions after 500 years, each figure's hands positioned differently. The interior smells of cold stone and old incense. Admission is 15 PLN (about 4 USD), the towers cost 25 PLN, and neither needs a reservation. Every hour on the hour a trumpeter leans from the north tower and plays the hejnał melody. It stops abruptly mid-phrase. The tradition commemorates a 13th-century watchman killed by a Mongol arrow during the 1241 invasion.

Wawel Hill sits at the southern end of the Old Town, a 10-minute walk from Rynek Główny along Grodzka Street. The castle complex has stood here since 1001. Wawel Cathedral, consecrated in 1020, is where Polish kings were crowned and buried for five centuries. The Sigismund Bell, cast in 1520 and weighing 11 tons, rings on national holidays. You can feel the vibration through the stone floor when it sounds. The Renaissance courtyard, rebuilt after a 1499 fire by Italian architects under Sigismund I, has three tiers of arcaded loggias with Florentine proportions. Morning light at 9am catches the cream-coloured limestone and turns the arcade shadows a sharp blue. State Rooms tickets cost 35 PLN, Crown Treasury 30 PLN. Buy morning slots online at least 3 days ahead in summer because the daily visitor cap fills by 10am. The cathedral is free, but the royal crypts and bell tower cost 18 PLN. Mind you, the hill itself costs nothing. From the western terrace, the Vistula bends northeast toward Podgórze, and on clear mornings you can make out the Tatra peaks 100 kilometres to the south.

Wieliczka Salt Mine sits 14 kilometres southeast of the city centre. Minibuses run from near Kraków Główny station to the mine entrance in about 30 minutes, or a taxi costs around 60-80 PLN. The mine opened in 1300 and descends 327 metres over 9 levels. The tourist route covers 3.5 kilometres at depths between 64 and 135 metres. Temperature underground holds steady at 14°C year-round, so bring a layer even in July when the surface sits above 25°C. The Chapel of St. Kinga, carved from rock salt 101 metres below ground, is 54 metres long and 12 metres high. The chandeliers are salt crystal. The walls taste faintly of salt if you run a finger along them and touch your tongue. Everyone does. The guides expect it. Standard adult tickets cost 120 PLN (about 32 USD). Book online at least 2 days ahead in summer. English-language tours leave every 30 minutes between 8:30 and 17:00, and the full tour takes roughly 2.5 hours. This is the one Kraków-area attraction that needs advance booking. Walk-ups in July and August get turned away by mid-morning.

A note on what to skip your first day. Kazimierz, the old Jewish quarter south of the Old Town, is worth a full afternoon but not day one. Save it for day two when you have your bearings. The same goes for Schindler's Factory museum at Lipowa 4 in Podgórze, which needs a timed ticket (29 PLN) and takes 90 minutes to absorb properly. For your first 6 hours in Kraków, the right sequence is Rynek Główny and St. Mary's in the morning, Wawel after lunch, and an early dinner at a bar mleczny (milk bar). Try Bar Mleczny Krakus near Miodowa for pierogi ruskie at 12-15 PLN a plate. The dumplings arrive steaming, the dough slightly translucent, filled with potato and farmer's cheese. That is a better first evening in Kraków than any sit-down restaurant on the square, where the same pierogi cost 35-45 PLN and come with a 10% service charge.