Blood in your legs has to climb back up to the heart against gravity, with almost no pressure behind it. Watch the muscle pump and one-way valves do the work.
The muscle pump
Venous returnclimbing back to the heart
Three helpers
๐ท Reference image
A real labeled figure to compare with the interactive above.
Venous Return โ OpenStax, CC BY 3.0 (via Wikimedia Commons)