Total solar eclipse passes over United States

What started as a tiny crescent of the moon's shadow turned into a perfectly beautiful eclipse in the late morning hours in Oregon.

The total solar eclipse made a diagonal trek across the country. It ends in South Carolina just after 4 p.m. Eastern.

See eclipse-viewing photos from around the country

NASA is having a bit of fun with it, tweeting a joke about the moon blocking the sun — on social media.

 

"HA HA HA I've blocked the Sun! Make way for the Moon," said the official NASA Moon account, which blocked the NASA Sun's account.

If it hasn't yet reached your area, here's what you can do to be prepared:

-- Keep up with the forecast to make sure you won't be rained or clouded out.

-- Make sure you know everything about safely viewing the eclipse.

-- Any animals nearby? Keep an eye on their behavior.

-- Look on social media to see how all the various science experiments are going.

-- If you're stuck inside, follow along with virtual reality and 360 video on CNN.

-- Get your camera or phone ready!

-- Don't have glasses? Here's how to make them in less than 10 minutes.

-- Watch Bonnie Tyler sing "Total Eclipse of the Heart."

-- Read all the tweets and reactions or follow CNN's live blog.

-- Anything you don't see here? It's in our last-minute cheat sheet.