We present a 1 megapixel single-photon avalanche diode (SPAD) camera featuring 3.8 ns time gating and 24 kfps frame rate for 1-bit images, fabricated in 180 nm CMOS image sensor technology. The SPAD sensor was used to capture 2D and 3D scenes over 2 m with depth resolution of 5.4 mm and precision better than 7.8 mm (rms). We demonstrate extended dynamic range in dual exposure operation mode and show spatially overlapped multi-object detection in single-photon time-gated time-of-flight experiments. We further demonstrate applications of the megapixel SPAD camera for fluorescence lifetime imaging microscopy (FLIM) and light-in-flight imaging.