I was on a first date with my current girlfriend Emillie. We decided to walk up the Tuna Canyon Park Trail in Topanga Canyon, to look out over the ocean. We sat in one spot for 3-4 hours, watching the sunset. The approximate coordinates are 34.059538, -118.616345 (34º 03′ 34.33″N 118º 36′ 58.84″W)Just before the sun went down, there was a cloud NW, about 10 miles off the coast of northern Malibu. It was glowing and pulsating with a deep magenta and blood orange color, undulating and changing in color, but staying constant in form. It just looked like the sun's curved vibrations were causing a visual light illusion.Within minutes of the sun going down, I mentioned to Emillie that Google Maps had released the underwater topography of much of the Earth. I briefly mentioned the strange underwater formation 6.6 miles off the coast of Malibu, which gave the illusion of looking like an underwater base, with a flat plateau as a ceiling, and 600ft+ columns. At the time I knew this may have been a distortion of satellite information that caused the structure to look like it has a dark interior that could be entered from beneath the ocean.About 2 minutes after mentioning this, at approximately 7:30PM, we noticed a gigantic bright white dome floating on the ocean. It was approximately 6-7 miles off the coast of Malibu, exactly above the location of where the "base" is shown on Google Maps. It wasn't necessarily a UFO, or a USO, but a "UBO" - an unidentified buoyant object. It must have been 300-1000ft+ large. Although it appeared like a perfect white dome, it may have been a sphere half submerged in the ocean, although we could not perceive any extra light from below the surface. Within a minute and a half of staring at this motionless anomaly, it began to move west into the horizon at an alarming speed, and actually went completely into the horizon out of visible range within 20-30 seconds, at thousands of MPH.