What country recently planted a flag at the bottom of the North Pole seafloor?

The answer is Russia

In August 2007, Russian Navy made a record-breaking dive to the Lomonosov ridge, which lies 2.5 miles beneath the North Pole

It was a symbolic move designed to show that Russia is claiming stake to the underwater ridge, which they say is connected to their continental shelf.

Many other countries are trying to claim the land including Canada, but the move by Russia was shown as the reminder that Russia can and will use its naval technology to claim Territory it considers vital to its national interests.

The ridge is home to billions of barrels of oil With melting ice caps it is becoming increasingly easier to exploit these regions and Russia wants to make sure it can benefit from this early on.