A neighborhood watch volunteer stands guard on her street on February 9, 2017 in Peronia, Guatemala. Residents of Peronia, south of Guatemala City organized block by block to secure their community after ten of their neighbors in January were killed, they say, for refusing to pay extortion money to gangs. Armed with machetes and sticks, residents take turns each night, baring strangers' entry into their neighborhoods. Violence and poverty continue to drive emigration from Central America to the United States, even as the Trump administration moves to tighten border security. (Photo by John Moore/Getty Images)

Centenarian Sikh runner Fauja Singh poses for pictures after being the first person to officially enter for next year's Edinburgh Marathon on September 1, 2011 in Edinburgh, Scotland. A world record holder, aged 100, Fajua Singh has run seven marathons, all after his 89th birthday. He officially opened the entry process by signing up for his last ever 26 mile event in Edinburgh. (Photo by Jeff J Mitchell/Getty Images)

A competition, now in its 43rd year, dedicated to showcasing the beautiful and bizarre as seen under a light microscope attracted over 2,000 entries from 88 countries. Here: Honorable Mention by Emre Can Alagöz, Istanbul, Turkey: The eyes of a jumping spider, magnified 6x. (Photo by Emre Can Alagöz/2017 Nikon Small World Photomicrography Competition)

With its huge eyes, comical name and diminutive size, Mark R. Smith’s image of a baby Hawaiian bobtail squid can’t help but raise a smile. A curiously endearing creature, the cephalopod is just 1.5cm across, its mantle cavity bearing more than a passing resemblance to a rather natty shower cap. But it is also a beautiful example of symbiosis – nature’s version of “I’ll scratch your back if you scratch mine” – for on the underside of the squid is a light organ which houses bioluminescent bacteria. The squid offers the bacteria protection and food, while the bacteria emit a glow – a handy trait that the squid uses to offset its silhouette, helping it to evade predators in the depths below. Mark R. Smith’s entry combines several images of a Hawaiian bobtail squid with different focus lengths to create a final picture with greater depth of field than normal. (Photo by Mark R. Smith/Wellcome Images/Macroscopic Solutions)

The Art Car Parade is the highlight of a three-day celebration of the drive to create: Art Car Weekend. But it all began with a donated 1967 Ford staton wagon and $800 worth of paint and plastic fruit. And now, 26 years later, it attracts 250+ vehicles (and other entries) from 23 states, Canada, and Mexico. Photo: An art car is seen on Allen Parkway during the 26th Annual Houston Art Car Parade on May 11 in Houston, Texas. (Photo by Scott Halleran)

The 26th annual National Geographic Traveler Photo Contest is now accepting submissions. Official categories include: “Travel Portraits”, “Outdoor Scenes”, “Sense of Place” and “Spontaneous Moments”. The contest is accepting entries until June 30. Photo: “Forest lights”. Aurora Borealis over the forest of the Pyhae Luosto National Park, Finland. (Photo and caption by Nicholas Roemmelt/National Geographic Traveler Photo Contest)

The competition is run by Royal Observatory Greenwich sponsored by Insight Investment and in association with BBC Sky at Night Magazine. This year astrophotographers from 91 countries sent in more than 4,200 spectacular entries. Here: The Milky Way rises above an isolated lighthouse in Tasmania. Shot by James Stone of Australia. (Photo by James Stone/Astronomy Photographer of the Year 2018)

Fireworks from Japan light up the sky at the start of the 6th Pyro musical competition Saturday, February 7, 2015 at the Mall of Asia shopping complex at suburban Pasay city south of Manila, Philippines. The fireworks competition, which runs for six consecutive weekends, features entries from 11 countries as host country the Philippines, Canada, United States, Japan, United Kingdom, Brazil, Portugal, China, Mexico, Italy, The Netherlands and Sweden, with Canada winning the championship last year. (Photo by Bullit Marquez/AP Photo)