On the last Friday in April, the U.S. celebrates National Arbor Day.
First held in 1872, Arbor Day is a meant to honor all of the sky-high sentinels around us, and also plant some new ones in an age of deforestation and urban sprawl. The event was founded in Nebraska, but has since spread to dozens of countries around the globe.
Even though the occasion is a great time to think about seedlings, domestic organizations like MillionTreesNYC and international groups like the Green Belt Movement are wonderful places to get involved year-round.
So before you go out and plant some saplings, take a look at some of the most famous, strange and awe-inspiring trees out there below.