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We think this square is a relaxed spot to wander on your own, though the paid tours that start here often fill up. A typical visit means joining a small group that also stops elsewhere. Book ahead if you want a guided option.

Gibralfaro Castle is a steep but rewarding stop above Malaga, with strong walls and wide views over the city and sea. We think the climb is worth it, and most visits are a simple walk around the grounds. Entry to walk the site is free. Wear good shoes and bring water.

You can walk around this Roman ruin for free, right in the middle of Malaga. We found it a calm spot to pause and look down into the old stone seating. Guided visits sell out, so book ahead if you want the full story with the cathedral and Alcazaba.

Constitution Square is a free, open plaza where you can wander at any time. We found it pleasant to pass through, though guided tours often use it as a meeting point. The queue for those tours is a nuisance, so book ahead if you want one.

We think Malagueta Beach works best as an easy, unscripted stop rather than a planned outing. It is a city beach, so expect sand, a promenade and plenty of nearby bars. Our advice is to arrive before midday in summer, since the sand gets packed and shade is scarce.

El Caminito del Rey is a dramatic walkway through a narrow gorge, and we think the experience lives up to the fuss. Visits usually mean a guided group moving along the path with plenty of photo stops. Book ahead, since tickets sell out quickly.

The Alcazaba is a calm, walled Moorish fortress above the city, with gardens, fountains and sea views. We found it a pleasant place to wander, and most visits here are short walks through the courtyards. Go early to avoid the heat.

The National Maritime Museum sits in a grand old naval building with ships to climb and maps to pore over. We found it calm and roomy inside, though the ticket line outside moves slowly. Book ahead if you want a guided tour, since those sell out.

The Mint Tower is a handy landmark on the canal ring, and wandering past it costs nothing. We think the paid boat trips that start here are the real draw, and they tend to fill up. Book ahead if you want a seat.

Westerkerk is a working church with a tall tower and a calm interior. We think it works best as a quiet stop while you walk the canals. Most visits here are short looks inside or walks past. Book ahead for the tower, and note the queue is the problem.

A canal cruise along the Herengracht is a relaxed way to see Amsterdam from the water. We found the open boats best for views and the drinks keep things social. These trips sell out, so book ahead if you want a specific time.

Amsterdam Central Station is a grand old building right in the middle of things, and wandering through it feels like stepping into the city's daily rhythm. We found it handy as a starting point for canal cruises and day trips, though it gets crowded. If you plan a guided visit, book ahead since those often sell out.

Zaanse Schans feels like a working village of windmills and workshops, and wandering it costs nothing. We found the tours usually bundle it with other towns, so you get a taster rather than a deep visit. Go early on your own to see the mills before groups arrive.

The Rijksmuseum holds centuries of Dutch art in a grand building, and we think it rewards a slow wander. Visits usually pair the galleries with a canal cruise or a small group tour, so the day fills up fast. Book ahead, since entry slots often sell out.

We like the Amstel for a slow wander along the water. It feels open and calm, and most visits are just strolling the banks and watching boats go by. Book ahead if you want a cruise, since those fill up. Walking the river itself costs nothing.

We think this is one of the best free viewpoints in Lisbon. You can walk up and take in the city and river without paying a cent. The paid tuk tuk tours that stop here also cover other parts of town. Book ahead if you want a guided option, as those sell out.

Lisbon Cathedral feels like a calm, dim sanctuary in the middle of a busy part of town. We found it worth a short stop to see the cloisters and the old stone work. Visits often sell out, so book ahead if you want a guided tour.

We think the castle is worth a look, though the crowds can wear you down. The queue is the problem, and it often sells out, so book ahead. Go early or late for calmer ramparts and views over the city.

Cabo da Roca is a windswept cliff where Europe ends, and the views are worth the trip. We found it pairs well with Sintra and Cascais on a day tour. Walking around is free, but the queue is the problem. Book ahead if you want a guided visit.

Sintra feels like a storybook town of palaces and gardens, and we think it earns its popularity. Days here are long and packed, often paired with Cascais and the coast, so expect a full outing. Book ahead since visits sell out, and skip-the-line tickets help because the queue is a real problem.