A glacier-fed river in Asia is the focus of today's Geo Quiz.
Can you name the 1,800 mile long river that originates in Tibet, high in the Himalayas, then winds its way south through India and Bangladesh before it finally empties into the Bay of Bengal?
The river provides drinking water for millions of people along the way, as well as hydro power and irrigation to farmers.
But climate researchers say some of the high altitude glaciers that are the source of this river are melting fast.
Aaron Putnam a research scientist at the Lamont-Doherty Earth Observatory at Columbia University traveled to Bhutan to investigate one of these massive glaciers up close.
"It's this ice field that caps a beautiful series of mountains, and it pours over a cliff in a series of ice falls that resemble teeth so we call it the dragon tooth glacier," Putnam said.
That's the name of the Himalayan glacier…but what's the name of the major Asian river to the south?
The answer to our Geo Quiz takes us to the remote Himalayan nation of Bhutan. Climate research scientist Aaron Putnam is part of a team investigating the effects of changing climate on temperature, precipitation and glaciers in Bhutan – and implications for water supplies of 1.3 billion people downstream along the Brahmaputra River.