In the 1930s, seismologists faced a big mystery about the inner structure of the Earth. Today, on what would have been Danish seismologist Inge Lehmann's 127th birthday, it's a good time to appreciate how - using limited data and rudimentary technology - she brilliantly arrived at the answer.

This allows you to see proposed, active and finished (cleaned up) superfund sites around the country. Pretty interesting.

Map of all the submarine cables on earth. How the internet gets from place to place.

Since the beginning of this year, the levels of air pollution in Beijing have been dangerously high, with thick clouds of smog chasing people indoors, disrupting air travel, and affecting the health of millions. The past two weeks have been especially bad -- at one point the pollution level measured 40 times recommended safety levels.

Jackson, Wyoming, is an unlikely place for urban farming: At an altitude over a mile high, with snow that can last until May, the growing season is sometimes only a couple of months long. It's also an expensive place to plant a garden, since an average vacant lot can cost well over $1 million.

There's a lot of good information and visuals about population and emergent technologies in this letter, and it has a cool layout. Definitely worth reading.

This is an article with a short video about the new and biggest ships in the Maersk line. I thought it might be worth looking at for the economics, resources or some other units.

Explore BBC Earth's unique interactive, personalised just to you. Find out how, since the date of your birth, your life has progressed; including how many times your heart has beated, and how far you have travelled through space.

What do the climate experts say? How do scientists know the climate is changing? Climatica provides scientifically accurate information from the experts.

It is not every day you can announce the discovery of thousands of new mountains on Earth, but that is what a US-European research team has done. What is more, these peaks are all at least 1.5km high. The reason they have gone unrecognised until now is because they are at the bottom of the ocean.

CCTV camera footage of Japanese tsunami, funny if it wasn't so tragic.

Hans Rosling's Ignorance Survey. Information about what global population actually looks like.

Bill Nye sea floor spreading clip.

This is Hans Rosling's website with lots of cool visuals, videos, etc. for teaching population.

This visualization displays the total number of earthquakes Japan experienced in 2011 including the massive 9.0 that led to the tsunami.