Unmistakable in their blue construction shrouds, 181 Fremont and the Salesforce Tower have become the dynamic duo of the San Francisco skyline. Rising virtually side by side, the two towers have now poked well above their neighbours, and their distinctive forms are instantly recognizable among the sea of condos and office towers that dominate the local cityscape.

181 Fremont (left) and Salesforce Tower (right), just right of centre, image by Flickr user Sergio Ruiz

Designed by Heller Manus Architects for the Jay Paul Company, 181 Fremont will eventually rise to a height of 802 feet. The 54-storey, mixed-use, 435,000-square-foot office and 67-unit residential tower will soon become a fixture on the downtown skyline, with signature diagonal bracing that sets it apart from the rest. 

181 Fremont on the rise, image by Flickr user Patrick Boury

Equally iconic, the nearby Salesforce Tower, designed by Pelli Clarke Pelli Architects and Kendall/Heaton Associates for Boston Properties and Hines, will rise to a height of 1,070 feet. The 1.4 million-square-foot 61-storey supertall office tower will gradually taper to a rounded peak, where the tower's signature decorative crown caps off the project. 

Salesforce Tower on the rise, image by Flickr user Patrick Boury

Once complete, 181 Fremont and the Salesforce Tower will dramatically add to the skyline, their combined presence to forever change its size and scope. San Francisco's downtown core is in the midst of a development boom that has been underway for the better part of a decade. 

Salesforce Tower (left) and 181 Fremont (right), both to the right of Market Street, image by Flickr user Sergio Ruiz

SkyriseCities will be sure to return to both of these projects as progress continues. For more information on 181 Fremont and the Salesforce Tower, check out the Database files (here and here) and the Forum threads (here and here), and as always, feel free to join the conversation in the comments section below.