Turning off cooling and or heating but leaving the fan on

We recently had a lovely day (temperature) and wished to turn the Nest off but keep the fan on the furnace running. We turned off the auto schedule and the auto learning. The AC turned off but the fan continued running (as we wished). At 8:00 the AC came back on, without us touching a control. How do we prevent this from happening? I suppose I could go in and remove every setting that the Nest has learned for a week, but that seems pointless. There must be a way to just tell it to stop doing anything automatically until we want it to again?

Thanks