The majority of the earth's surface is ocean, and it's a rare soul who wants to stay on it when landfall breaks are possible. But map nerds have studied the question of how far you can go in a ship without steering or running into land. It's hard to decipher on a flat map; that's why we should all have a globe available to study. One redditor proposed such a route in 2012, and now two computer scientists have confirmed his idea.
According to the researchers, the path from Pakistan to Russia is indeed the longest straight path possible without hitting land. It measures 19,939.6 miles, just about 5,000 miles short of the planet's circumference. The researchers also found the longest straight-line path across land, from Jinjiang in China to Sagres in Portugal, measuring 6,984.9 miles.
If you don't have a globe handy, or you can't make it spin against it's own axis (which is likely), you can see a video of the route drawn perfectly straight at Popular Mechanics. -via Metafilter
I never heard that about metres vs. meters; it makes sense.
Also, a 'kilometre' is not a device that measures kilos, so it does not rhyme with 'thermometer' and 'altimeter'. A kilometre is a unit of distance, so it rhymes with 'centimetre' and 'millimetre'.