If the most popular foods of Rio de Janeiro have one thing in common, it is their informality. You can find fine restaurants in the city, but they do not set Rio apart from other places. What does set it apart, and what invariably brings its residents, known as "Cariocas," together is the unpretentious food they eat in bright, loud, crowded bars and restaurants, on busy street corners, or after a day at the beach. Here: A view of traditional bolinhos de bacalhau (fried codfish balls) in Rio de Janeiro, Brazil, May 7, 2016. (Photo by Sergio Moraes/Reuters)

A girl peers from between light decorations at a Christmas fair which opened ahead of the holiday season in Bucharest, Romania, Friday, November 25, 2022. Municipal authorities in the Romanian capital, quoted by local media, stated that holiday season city light decoration levels will remain at last year's level and use energy saving solutions. (Photo by Vadim Ghirda/AP Photo)

A new book of photos by legendary photographer Weegee shows what industrialized, pre-gentrified New York looked like in the mid-20th century, before the city was crammed with towers and billboards. Here: this combination shows the 1945 photo “Derelict sleeping on the sidewalk outside police headquarters” by Weegee, provided by the International Center of Photography in New York, and a woman walking on the same spot on Wednesday, March 18, 2015. (Photo by AP Photo/Copyright Weegee/The International Center of Photography, Mark Lennihan)

Google has built its first self-driving car prototypes and hopes to test hundreds more models this summer. If all goes well, the company is planning a pilot program in California over the next few years.

If we were to burn NH4Cr2O7 with HgSCN in the Dark Ages in Europe and show it to anyone, it is us who would be burning next on a fiery cross of Inquisition. And it’s no wonder, since this experiment produces a truly marvelous result. At first, as you ignite the mixture of NH4Cr2O7 and HgSCN, all you can see is that it is slowly burning with a reddish flame. After a while, however, a crater is formed in the middle of the burning pile, and then, suddenly, tentacle-like appendages start sprouting from the burning mixture. And you can almost hear the scream of the mad occultist – “Come forth, Kraken! Come forth!” But of course, this is simply a chemical reaction that is called the "Pharoah's Serpent". It was also often sold in firework stores until people realized that it was toxic.

“The scientists behind NASA's $2.5 billion Curiosity rover mission on Mars on Tuesday explained the nature of a tiny, gleaming "flower" embedded in Red Planet rock, and revealed where they'll be using the SUV-sized robot's drill for the first time”. – Alan Boyle via NBCNews.com

Photo: Scientists say that a “Martian flower”, seen here in an image from the Curiosity rover's Mars Hand Lens Imager, is a 2-millimeter-wide grain or pebble that's embedded in the surrounding rock. Another, darker-colored mineral grain can be seen above and to the left. (Photo by NASA)

“Nachos are a popular corn based food of Mexican origin associated with Tex-Mex cuisine that can be either made quickly to serve as a snack or prepared with more ingredients to make a full meal. In their simplest form, nachos are tortilla chips or totopos covered in melted cheese and salsa. First created circa 1943 by Ignacio "Nacho" Anaya, the original nachos consisted of fried corn tortillas covered with melted cheddar cheese and pickled jalapeño peppers”. – Wikipedia

Photo: Workers put the finishing touches on the nachos as Ninety Nine Restaurants in Billerica, Massachusetts set a new world record by creating the Guinness World Records World's Largest Nachos, weighing in at 3,999 lbs on October 1, 2011 in Billerica, Massachusetts. (Photo by Gail Oskin/Getty Images for Ninety Nine Restaurants)

In this October 18, 2015 photo, contestant Carlos Angevil, Miss Gay Vargas, competes in the swimsuit category of the ninth annual Miss Gay Venezuela beauty pageant in Caracas, Venezuela. Miss Gay Venezuela requires contestants be younger than 37 and be at least 1.7 meters (5' 6" feet) tall. (Photo by Ariana Cubillos/AP Photo)