Poznań is now Poland's fifth largest city. It is sometimes claimed to be the first capital of the kingdom of Poland. Poznań has many historic buildings and sights. The European Football Championship will take place in Poznan 2012.

Photo by: tiseb ; Source: Flickr

Shaun Gibson prepares some of the 5.5 tonnes of fireworks at Edinburgh Castle ahead of the city's Hogmanay celebration on December 29, 2011 in Edinburgh, Scotland. Over 2,800 individual fireworks from six specialised firing panels will be launched during the display over Edinburgh Castle and gardens. (Photo by Jeff J Mitchell/Getty Images)

Men look out from a carriage train as it leaves from the Nizamuddin Railway Station on February 06, 2012 in New Delhi, India. The Nizamuddin Railway Station serves as the main station connecting all major cities, and is served by Northern Railways. (Photo by Daniel Berehulak/Getty Images)

Visitors attend a press preview of the 2012 Whitney Biennial at the Whitney Museum of American Art on February 27, 2012 in New York City. The contemporary art exhibition includes sculpture, photography, painting, installations, dance, theater, film and music and runs from March 1 through May 27. (Photo by Mario Tama/Getty Images)

America may be a nation obsessed with automobiles, but today the bicycle is giving the car a run for its money. And while New York is just one of many cities that is implementing new bikefriendly policies, the local cyclist population stands out as one of the most diverse, inventive, and stylish in the world.

Prada Marfa is a permanently installed sculpture by artists Elmgreen and Dragset, situated 1.4 miles (2.3 km) northwest of Valentine, Texas, just off U.S. Highway 90 (US 90), and about 26 miles (42 km) northwest of the city of Marfa. The installation was inaugurated on October 1, 2005. The artists called the work a "pop architectural land art project."

The CBRE Urban Photographer of the Year competition – now in its ninth year – encourages professional and amateur photographers to capture cities at work. Here: Dog Walker – 15:00. The competition allows photographers to enter up to 24 images, one representing each hour of the day. (Photo by Johanna Siegmann)

“Rivers Forgotten” is a journey through the passages and portals of the underground waterways that lie unseen below cities. Self-taught photographer Jeremy Kai brings these forgotten landscapes to light. Photo: Beneath the Toronto area, 2011. (Photo by Jeremy Kai)