Bottom line: for first-timers, choose Venice (romantic canals, car-free, coverable in 2–3 days); Milan suits longer stays, shopping, food and nightlife, and works as a gateway to Lake Como. Venice's highlights are St Mark's Basilica, the Grand Canal, Doge's Palace and Rialto Bridge — the whole city runs on walking plus vaporetto water buses (no cars), but it gets very crowded in summer and is pricier (an access fee applies on peak days). Milan is known for the Duomo, Galleria Vittorio Emanuele II, Leonardo's Last Supper and La Scala, with easy metro/tram links and fewer tourists; try risotto alla Milanese, osso buco and aperitivo culture. The two cities are about 245 km apart, ~2h15 by high-speed train. Suggested: 2–3 days Venice, 3–4 days Milan (plus Lake Como).