Starship!

They stacked the tallest, most powerful rocket to be built, today, in Texas. When Spacex's Starship 20 was placed atop its booster, it surpassed the tallest rockets ever stacked.  It's taller than the Saturn V from the Apollo Moon missions, which is the tallest, most powerful rocket ever launched.

When Starship 20 launches, it will become the most powerful to ever launch.  Saturn V dwarfed any other before or since, including the Space Shuttles.  As awesome and enormous as that was, Starship is bigger.