The Saint Louis Art Museum in Missouri, US is to undergo its first major expansion in more than 20 years.

Designed by London-based architect David Chipperfield, the expansion - in excess of 200,000sq ft - will provide new galleries, public space and a 300-space underground car park, as well as a new, fully accessible entrance on Fine Arts Drive. The project will result in a 30 percent increase in the museum's gallery and public space, and will more than double its current parking capacity.

As part of the project, the historic Cass Gilbert building will be improved, with over 13,000sq ft of space renovated for permanent collection galleries, education, classroom, and public use. The museum will remain open to the public whilst the work takes place and will continue to operate on its current schedule.