[For a list of the best squares in North America, click here.]

1. Rynek Glowny, Krakow, Poland

The largest square in Europe also happens to be the best. Rynek Glowny ("Grand Square") is so dynamic, it pulls you in from anywhere in the city. All roads in Krakow lead you here, and the closer you get, the livelier the streetlife becomes. There is so much going on in this square--at least twenty different attractions at any given time--that it makes our "Power of Ten" rule seem inadequate.

2. Plaza Hidalgo, Mexico City, Mexico

This square is an important center of community life in the Coyoacán neighborhood of Mexico City. A neighboring church, Iglesia San Juan Bautista, is an oft-visited site for both residents and tourists, but the park is the real glue that holds the area together. Although the design consists of a formal set of linear paths, Plaza Hidalgo functions quite flexibly, allowing visitors to circulate freely between different sections. On a typical day, one side of the plaza throngs with people at market stalls; vendors at another spot draw people with their fresh lemonades and ices; in still another area, they congregate around benches and a small fountain under the shade of trees. These artfully placed amenities act as focal points, which create activity throughout the plaza. Rather than dictating where people can go, these linear paths act as connections between various destinations in the park. It is consistently active and we think it is one of the finest destinations anywhere in North America.

3. Piazza Navona, Rome, Italy

When asked, "What is the greatest square in the world?", many would say Piazza Navona. Why? Because it has all the qualities that a great square should have: major attractions, such as Bernini's great fountain; excellent programming (including one of the world's best Christmas markets); lively uses at the edges; and a design so flexible it is filled with people even at night and in the dead of winter.

4. Piazza del Campo, Sienna, Italy

For anyone fortunate enough to ever visit Sienna, this square inevitably makes the most vivid memory. Like Rynek Glowny in Krakow, Piazza del Campo defines the city. It may be the foremost example of how a square's influence can extend, like the tentacles of an octopus, through the surrounding streets. Plus, the layout, in which one can see everything in the square from any corner, makes it a fantastic place to watch people.

5. Piccadilly Circus, Trafalgar Square, Covent Gardens, and Leicester Square, London, United Kingdom

Trafalgar Square.

Together, these four squares form the heart of central London. No other city has four public spaces of such high quality so close to each other. Over the past 30 years they have been intelligently shaped and managed so that they keep getting better. The result is the most dynamic core of any city in the world. The only comparison may be the souks of Fez or Marrakech in Morocco, which, though very different from London's squares, exhibit a similar tight-knit intensity.

6. Hotel de Ville (City Hall), Paris, France

No other city hall square comes close to this one. It is truly a model for cities around the world. Constantly full of activity, the Hotel de Ville draws on the unique qualities and assets of Paris itself. Whether it's a winter skating rink, an exposition of world cultures, or a faux beach with lounge chairs and umbrellas, this plaza is always good for a wonderfully innovative surprise.

7. Old Town Square, Prague, Czech Republic

You could easily and enjoyably spend a whole day here in the heart of Prague watching the comings and goings of tourists and locals. Although not a huge square, it caters to a number of distinct groups at the same time. The numerous young people gravitating to Prague sit on the edges of a striking art nouveau fountain, while tourists head for the stalls of a small souvenir market and well-heeled café society types take a seat at the outdoor restaurants in front of a historic Catholic church. And everyone waits for the famous clock to chime at the hour. It's also the crossroads of the city, with pedestrian links to the nearby Charles Bridge, the famous Jewish quarter, Charles University and the much larger Wenceslas Square.

8. Plaza de la Constitucion (Zocalo), Oaxaca City, Mexico

Strolling down the pedestrian walkway Macedonio Alcala, one arrives at the daily fiesta that is the zocalo. Sitting on benches, parents enjoy the soothing sounds from the fountains as they watch their children play. Vendors circumambulating the zocalo sell corn, chapulines and fruit to customers at the shoe shine stands scattered throughout the plaza. Friends gather on the benches to discuss events they read about in newspapers bought by the nearby newsstands. Every night, musicians serenade customers eating at the cafes. Although a poorly executed renovation undertaken in mid-2005 threatened to suck the life out of the zocalo, early reports indicate that it remains a beloved place and the center of civic life in Oaxaca.

9. Plaza Santa Ana, Madrid, Spain

This square is a comfortable place to spend a few hours day or night. Copious amenities and trees surround a promenade that invites pedestrians into the center. The surrounding streets have been aggressively downsized to narrow channels that make traffic move slowly through the space, allowing cars and people to coexist comfortably. Have a drink and eat some delicious olives at one of the many cafés around the square, while watching kids play pick-up soccer games.

10. Plaza de Armas, Cuzco, Peru

(Contributed to Great Public Spaces by Duncan Cameron)

Plaza de Armas is a beautifully landscaped plaza that traces its roots to the Inca Empire. Its abundant street life comes from the numerous cafés, restaurants, and stores that spill out from its edges. Many of the restaurants have outdoor tables, and there is constant entertainment throughout the day and night. The plentiful shade, benches, sitting walls and steps also make the plaza a popular lunchtime destination. Historically, the Plaza has served as the city's primary meeting place and it continues in that role today.

11. Trg Bana Jelacica, Zagreb, Croatia

This vibrant square, adjacent to the wonderful Dolac Market, is the center of action in Croatia's greatly underrated capital city. Reminiscent of Vienna's squares, it is the outdoor living room of Zagreb. It functions both as a destination--with a number of places all its own--and as a central connection between many parts of the city. Several of Zagreb's tram lines go along the edge of the square, providing easy transit access and adding to the hustle and bustle of the place.

12. Östermalmstorg, Stockholm, Sweden

Since a 1990's re-design made Stockholm's Kungstradgarden (King's Garden) much more rigid and less user-friendly, Östermalmstorg has become the city's best square. Anchored by a beautiful market hall (Saluhallen), this square is a neighborhood destination. It remains a great example of what Kungstradgarden used to be: a flexible space with uses that respond to the neighborhood and the changing seasons.

13. Plaza de Entrevero, Montevideo, Uruguay

One of several well-functioning civic squares in Montevideo, this one has all the uses of a traditional zocálo, while letting go of the formal layout. This has resulted in a variety of spaces that support a much broader range of activities and experiences than would be possible with a more rigid design. The simple combination of a café area, playground, and bus stop, for instance, is one of the few instances anywhere that such complementary uses have been layered together. The best layering can be found in the relationship between the seating options, pathways, and access to the central fountain--which enables an endless variety of active and passive uses.

14. Federation Square, Melbourne, Australia

(Contributed to Great Public Spaces by Fiona Whitworth)

Federation Square provides a unifying square for Melbourne, a place to gather and meet in times of fun and in times of protest. Situated on the busiest intersection in central Melbourne, across the road from Flinders Street Train Station and at the most prominent section of Melbourne's busy tram network, there is no other place in Central Melbourne that is as easy to get to. It is the size of a city block, incorporating an array of attractions, including fine art venues and a vibrant calendar of events, in addition to a broad range of restaurants, cafés and shops.

15. Imam Square, Isfahan, Iran

(Contributed to Great Public Spaces by Pradip Joshi)

Image © Caravanserai-Tours.com

Imam Square is the central meeting place of Isfahan, a city of a million people that in the past has served as the capital of Iran during three different historical periods. Lined with shops and cafés, it is also the site of two magnificent mosques -- Imam Mosque and Luftallah Mosque. These stunning buildings are a big reason behind Imam Square's reputation as one of the world's most beautiful public spaces. Even though attractions such as the mosques have made Isfahan one of Iran's main tourist destinations, Imam Square remains first and foremost a place that embodies local civic pride.

16. Campo Santa Margherita, Venice, Italy

This long courtyard is the social heart of the Dorsoduro district of Venice. The buildings encircling the area, some dating back to the 14th century, are home to a great mix of private residences as well as restaurants, bars, a weekday market with flowers and produce, and off-beat shops that provide interest throughout the entire day. The nearby university also helps add vitality. More of a spot for locals than for tourists, the Campo feels a long ways from the souvenir shops and trinket vendors in the tourist-dominated parts of Venice.

For information on more of the world's greatest squares, see PPS's Great Public Spaces website and click on the parks list.