the first will happen is was the newspaper will make big this news...
news about Bitcoin back to touch ATH will spread everywhere. The value of Bitcoin will certainly skyrocket, we don't know at what price the Bitcoin HYPE will stop.
Continuous interest coming from new investors will be seen, expect that news and mass medias to show interest after new ATH has been reached.
Knowing that emotions will drive around, people will create new high as fomo's will keep the run to continue pushing the value and try reaching another
ATH.