Our world is becoming more and more urban. Today, as Dwell contributor Mark Lamster reported for our June 2010 Megacities issue, more than 75 cities boast populations of more than 5 million. While 100 years ago 10 percent of the earth's inhabitants were urbanites, now 50 percent of us are city slickers. And the number's going up. By 2030, projections predict that 60 percent of the world's population will live in urban areas and by 2050, that percentage is expected to reach 75. In reaction to these leaping figures, the Institute for Transportation and Development Policy, based in New York City, commissioned ten architecture firms to each create a design for one of ten specified major international cities, envisioning what each city could look like in 2030 if we start putting in place today the mechanisms for sustainable futures via thoughtful public-transportation planning. The cities tackles: Buenos Aires, Argentina; Rio de Janeiro, Brazil; Guangzhou, China; Budapest, Hungary; Ahmedabad, India; Jakarta, Indonesia; Mexico City, Mexico; Johannesburg, South Africa; Dar es Salaam, Tanzania; and New York City; United States. The architects invited: PALO Arquitectura Urbana, Fábrica Arquitetura and CAMPO aud, Urbanus Architecture & Design, Varos-Teampannon and Kozlekedes, HCP Design and Project Management, Budi Pradono Architects, arquitectura 911sc, Osmond Lange Architects and Ikemeleng Architects, Adjaye Associates, and Terreform and Michael Sorkin Studio. The result is Our Cities Ourselves, an exhibition that opened at the AIA New York's Center for Architecture in New York. The show, which displays the ten visions, closes on September 11 then packs up and travels to China, Brazil, and Mexico. For more, visit cfa.aiany.org or ourcitiesourselves.org.