On Nov. 25, 1758, British Gen. John Forbes occupied the smoldering ruins of the French-built Fort Duquesne.

Located at the forks of the Allegheny and Monongahela, the site was renamed Pittsburgh in honor of William Pitt, the then-British secretary of state.

This year, Pittsburgh is celebrating its 250th birthday in grand style with a series of special events in which art is playing a major role.

Ranked third-best in the nation as an arts destination among other mid-size cities by American Style magazine, Pittsburgh is capitalizing on its wealth of art museums and galleries by making them a major component of the anniversary celebration. First and foremost was the May 3 opening of the 55th Carnegie International, the oldest exhibition of international contemporary art in North America and the second oldest in the world.

Founded in 1895, the International is held every three or four years in the Pittsburgh Museum that bears Carnegie’s name. This year, however, marks the first time in its 112-year history that the exhibit has a title other than the Carnegie International.

“'Life on Mars' is very much a poetic gesture in terms of thinking about our place in the universe as humans,” said exhibition curator Douglas Fogle. “The thematic premise behind the show has to do with the idea of the intimate moments in our daily life that we miss by walking through our worlds and not seeing what is right in front of us. It also has to do with the more infinite sense of being part of the larger universe and finding ourselves on the inside and looking out.”

This year’s International, whose title is appropriated from a David Bowie hit song, runs through Jan. 11 and includes the work in many media of 40 artists ranging in age from 29 to 89 from 17 countries.

Throughout the remainder of the exhibit, a series of lectures, performances, classes and other related events have been scheduled.

On Pittsburgh’s North Side, the Andy Warhol Museum may be one of the most comprehensive single-artist museums in the world and one of only a handful in the nation, but it is often also the home of some very captivating traveling exhibitions.

Besides being the repository of some 800 paintings, nearly 100 sculptures and 2,000 works on paper, and close to 4,000 photographs related to one of the most influential artists of the 20th century, the museum is showing a special exhibit of 24 abstract paintings by Dutch artist Piet Mondrian, many of which have never been seen in the United States. It runs through Aug. 31.

“The paintings are arranged in roughly chronological order, starting with the 1907 ‘The Red Cloud’ and ending with ‘Composition with Blue, Yellow, Red, Black and Grey,’ completed in 1922,” said Tom Sokolowski, museum director.

Running simultaneously with the Mondrian exhibit, “Transformer: The Work of Glenn Kaino” is a collection of 12 installation works created by the Los Angeles artist know for his large-scale, mixed-media and kinetic sculptures. The exhibit runs through August 31.

Also on Pittsburgh’s North Side in the historic Mexican War Streets district, a preserved zone of roughly 300 houses built between the 1850s and 1890s, the Mattress Factory has worked with more than 300 contemporary installation artists, including John Cage and James Turrell, since its founding in 1977. Housed in what used to be a mattress warehouse at 500 Sampsonia Way, the cutting edge art institution is showing site-specific works by nine artists from six countries in an exhibit titled “Inner and Outer Space.”

The title’s theme not only serves as the conceptual underpinning of the exhibition, the artists also have created installations that extend from the inside to the outside of the gallery building in a visceral way. The exhibit runs through Jan. 11.