The DEAP-3600 experiment is searching for WIMP dark matter with a 3.3 tonne single-phase liquid argon (LAr) target. Detector construction was completed at SNOLAB in 2016, and the experiment is currently taking physics data. Results from 1 year of open data (758 tonne-day exposure) were recently published, demonstrating stable detector operation and the power of pulse shape discrimination to reject electron-recoil backgrounds in LAr. This background-free search currently provides the most sensitive WIMP-nucleon scattering cross section limit on a LAr target for WIMP masses above 30 GeV. This talk will focus on the design and construction of the DEAP-3600 detector and on the recent physics results.