1 William Street, Brisbane, Modern office tower in Brisbane, Australia

1 William Street is a 267-metre modernist office tower in the Brisbane CBD, designed by Woods Bagot and completed in 2016. Its dark reflective glass facade is set in a grid of vertical and horizontal mullions, with a sloped roofline and a curved base; a cylinder of diagonal bracing is visible on one side.

The block between William, Alice and Margaret streets held buildings from 1854, used for manufacturing, warehousing, shipping, housing and electricity generation, and was bisected by Short Street. The Queensland Government bought the properties from the 1960s, and from 1982 to 2013 the cleared 6,778-square-metre site served as a government car park. Cbus was named developer in December 2012, Multiplex began construction in 2013, and the tower opened in October 2016.

The building is nicknamed the Tower of Power, a reference to its all-government occupancy. Each floor's theme and colour scheme is dedicated to a Queensland icon or natural phenomenon, so corridors and lift lobbies differ from level to level. The site also yielded 137 archaeological features and about 600 artefacts from the 1850s to the 1900s.

The tower occupies a whole city block between William, Alice and Margaret streets and the Riverside Expressway, next to Parliament House in the Brisbane CBD. It is a working government building with 318 car bays and around 5,000 to 6,000 public servants inside, so plan to view it from the surrounding streets rather than the interior.

The site was excavated in 2013 before construction, yielding 137 archaeological features and about 600 artefacts, including ceramics and glassware from the 1850s to the 1900s. The finds pointed to Victorian values and varied domestic materials among the working-class residents who lived there.