1. Michelle Trachtenberg took us back to her Gossip Girl days with this photo of herself with her co-stars Penn Badgley and Chace Crawford hanging out on the set.
2. Madonna shared this photo of herself partying in the '90s with pals Kate Moss, Naomi Campbell, and Ingrid Casares.
3. Hillary Clinton took us back to her high school days.
It wasn’t always pantsuits and presidential races. Some of Hillary's best #TBT moments: https://t.co/PaBpGpWRbZ
4. Paul McCartney posted this photo of himself during the recording of the album Band on the Run.
5. Anderson Cooper in his pre-silver fox days.
6. Wilmer Valderrama shared this cute pic of him and his dad in the early '80s.
#TBT to when my dad looked like a #Narcos character.. And me a train conductor
