The Pacific Ocean is the biggest basin
The Pacific Ocean is by far Earth's largest ocean basin, covering an area of about 59 million square miles (155 million square kilometers) and containing more than half of the free water on Earth, according to NOAA. It's so big that all of the world's continents could fit into the Pacific basin.
Trees are breathing giants
When we think about big life, whales and elephants come to mind. But try on this tree for size: The General Sherman giant sequoia is the largest known stem tree by volume on the planet. The trunk of the tree contains slightly more than 52,500 cubic feet (1,486.6 cubic meters) of material. (Shown here, Giant Forest, Sequoia National Park.)
A huge fungus is the largest living thing
If you want to pinpoint the biggest organism on the planet, though, your best bet might be a really huge fungus. In 1992, scientists reporting in Nature revealed to the world a Armillaria, or honey mushroom, fungal organism that spans 2,200 acres in Oregon. There’s a slight chance that the offshoots of this mega-fungus aren't clones, but are simply closely related, but we’re in awe either way.
This bat is the world's smallest mammal
On the other end of the spectrum, there are plenty of teeny-tiny organisms on Earth, all the way down to single-cell life. But let's focus on something a little more cuddly: the Kitti's hog-nosed bat. This vulnerable species found in southeast Asia is only about 1 inch (29-33 millimeters) long and weighs only 0.071 ounces (2 grams), putting it in the running with Etruscan shrews, which are lighter but longer, for the world's smallest mammal. [World's Smallest Mammals]
Manila is the most crowded city
Don't like crowds? Stay away from Manila. This city in the Philippines is the most densely populated in the world, with the most people crammed into the smallest city limits (outlying suburbs don't count). As of the 2007 census, 1,660,714 people lived in 14.8 square miles (38.55 square kilometers).
Greenland has the most open space
Lovers of solitude might try Greenland on for size. This nation boasts the least population density of any on Earth. As of 2010, 56,534 people lived in 836,330 square miles (2,166,086 square kilometers) of elbow room. Most of the settlements in Greenland are clustered on the coast, however, so this low population density is somewhat misleading.
The Atacama Desert is the driest spot
The driest spot on Earth is the Atacama Desert of Chile and Peru. In the center of this desert, there are places where rain has never been recorded.
Roald Amundsen was first to reach the South Pole
Speaking of deserts, the first person to successfully traverse the desert of Antarctica to reach the South Pole was Norwegian Roald Amundsen. He and four other men used sleds pulled by dogs to make it to the Pole. Amundsen would later attribute his success to careful planning.
There are other Earth-like planets
Finally, there are almost surely more planets like ours. Space scientists have found evidence of Earth-like planets orbiting distant stars, including an alien planet called Kepler 22-b circling in the habitable zone of a star much like ours.
Whether any of these planets will harbor life is an open question.
More: All About Exoplanets from Space.com
The skies dazzle with dancing lights
Auroras occur when charged particles from the sun are funneled toward Earth by the planet's magnetic field and collide with the upper atmosphere near the poles. They are more active when the sun's activity peaks during its 11-year solar weather cycle.
The southern lights, also called aurora australis, are seen less often than aurora borealis, the northern lights, because few people brave Antarctica's dark, freezing winters. Shown here, a 2008 image taken from Antarctica of the dazzling sky lights. [See more amazing images of aurora]