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.

9-Year-Old Wows With Opera Singing An unforgettable voice is taking the world by storm. Amira Willighagen from Nijmegen wowed the crowd when she sang opera on Holland's Got Talent. The 9-year-old is self-taught and started singing out of sibling rivalry. Her brother took up violin, and she didn't want to be outdone. Her performance has now been viewed more than 2 million times.

Researchers Measure Top 3 Scariest Movies Which is the scariest movie of all? Researchers monitored heart rates as scary movies played, and the top three scariest movies were "Nightmare on Elm Street," "The Exorcist" and "The Shining." The No. 1 scene in "The Shining" that got those hearts racing was Jack Nicholson's "Here's Johnny" scene.

(Warner Brothers/Getty Images)

Best Cities to Trick-or-Treat In There's a new list of the best cities for trick-or-treating. No. 1 is San Francisco, then Boston, Honolulu, San Jose and Seattle. The criteria is maximum candy with minimum danger.