kickstandsup
Why not?
Starting January 2023, US citizens and others will need to register to travel in the Shengen area.
www.afar.com
Good for 3 years, nominal cost. Was originally going to take effect in 2021, but was postponed for obvious reasons.

U.S. Citizens Will Need to Register to Travel to Europe in 2024
Mark your calendars: The launch of the ETIAS travel authorization is currently slated for November 2023.

Good for 3 years, nominal cost. Was originally going to take effect in 2021, but was postponed for obvious reasons.