Whew, it's been such a fun day at NPR.

The staff showed up wearing their "I <3 NPR" tees. The Pleasant Pops truck came to the front of our DC offices just in time for a little mid-day treat. ATC produced a great show, just as it has done daily for the last 40 years. Today's show featured special remembrances from the past hosts.

We are especially thrilled with the birthday wishes on Twitter at #happybdaynpr, on NPR's Facebook page and elsewhere.

So, thanks for coming to our party. Without you, public radio's loyal listeners, we'd just be talking to ourselves.

Enjoy a glimpse of today's fun....

Even in our early days, NPR worked hard to produce and distribute the news using the best technical equipment and devices available. As you might imagine, we've come a long way from putting our stories together by editing reel-to-reel tape with razor blades.

Enjoy this look behind the scenes at our initial forays into advanced systems.

And, yes, enjoy the fashions too.

In the time since All Things Considered's first broadcast 40 years ago on May 3, 1971, a dozen hosts, supported by hundreds of staffers, have reported the news of the day, and a whole lot more.

Surely you'll be listening to ATC later this afternoon, right? You can expect to hear a little bit from each one of our former hosts.

Check out these photos of the hosts and staff over the last 40 years.

As we take a walk down memory lane today through 40 years of NPR, we thought you might like to see what your favorite NPR journalists looked like decades ago...and what they look like now.

NPR

NPR

NPR

NPR

We know you NPR listeners are a social bunch. You like to be informed and you take pride in sharing your knowledge with others. Okay, with everyone. Come on, you know it's true.

So, here's your chance to lead the way to the dance floor at NPR and All Things Considered's 40th Anniversary Party. Because we think 40 years of producing great journalism and thoughtful stories is a good enough reason to celebrate, everyone is invited to this party.

Tell your socially connected world that today you are celebrating NPR and ATC's 40th birthday.

On Facebook, feel free to surprise our social media team by dropping a birthday note to NPR's page.

We'd appreciate tweets at anytime, of course, but hope you'll help us out at 4pm ET today with a little experiment. We want to get a "wave" of tweets going through the Twitterverse when All Things Considered signs on. So, at 4PM (ET) today, just tweet what NPR person you'd most like to have cake with (and please tag it #happybdayNPR).

Also, do you happen to be looking for a new profile picture? Good news—we've got some great ones for you to use. Just right click on these images to the left, save to your computer and then upload to your profile.

Thanks for helping us celebrate.

Forty years ago today, on May 3, 1971, NPR debuted its first program: All Things Considered. Join us today for a celebration complete with photos from the archives and avatars for your Facebook profile. Happy Birthday NPR and ATC!

You'll want to keep refreshing this blog today, because we will come back to you with more birthday fun throughout the day.

Set up an appointment for yourself at 4pm ET today. We're hoping to get a "wave" of tweets going through the Twitterverse when All Things Considered comes on the air today. We'll tell you more later today over at @npr.

First up today: a glance through the NPR photo archives for a look at NPR over the last 40 years.