We generally consider that our mind is full of thoughts when we are awake. Like a river stream always running, we entertain our own dynamic mental stream: a thought can lead to another, relevant to what we do or not, ebbing between our inner life and the outer environment. How can the brain sustain such a thought-related mode constantly, though? A study just published in the Proceedings of the National Academy of Sciences indicates that it actually cannot, and that our brains also need to “go offline” for some moments, which we can experience as blanks in the mind.