You can also click the Add layer mask icon at the bottom of the Layers panel (which, by default, selects Reveal All). Note that if you already have a layer mask on the layer, this icon will change to Add vector mask. Or you can click the Add a Layer Mask icon in the Properties panel.
The top American ace of all time, the U.S. Ace of Aces was Richard Ira Bong. He shot down 40 Japanese planes in the Pacific. Over the years, there's been a lot of ink spilled about the relative scores of German and American aces. 27 Americans shot down over 20 enemy planes.
The Battle of B-R5RB was the largest and bloodiest in the history of warfare. More than 20 million soldiers were killed and more than 600 warships -- some of them kilometers long and capable of destroying lesser vessels with a single shot -- destroyed in a battle that raged for 22 hours.