From the unconventional and awe-inspiring to the hilarious and heartwarming, here's a look at some of the most interesting photos, videos and stories that have our newsroom talking today. What's capturing your attention, filling your inbox and cluttering your Facebook/Twitter feed? Tweet us the stories you're talking about using #InstantIndex, or email us at ABC.WorldNews@abc.com, and they could appear on "World News."

The Facebook Experiment

There's fresh outrage over that secret social experiment by Facebook. For one week in 2012, Facebook manipulated the newsfeeds of 700,000 Americans - pumping up positive posts from friends and families, for some; and negative posts, for others. Facebook then tracked how the posts made people feel.

They concluded that positive posts caused people to be happier and negative posts caused people to be sadder, aka: proof of an "emotional contagion."

Despite mounting anger, though, "like" it or not, you consented to Facebook's sociological experiment. Find out how so by clicking here .