Balls fly faster through thinner air and Madrid is 650 meters above sea level.

CNN: May 11, 2012 -- Updated 2124 GMT (0524 HKT)

Tuesday and is aiming for the roof of the mine workshop on Level 135 (135 meters above sea level).

CNN: STORY HIGHLIGHTS

Now I was maybe 5, 000 - 6, 000 meters above sea level, somewhere completely remote without any access to the outside world.

CNN: How a 'scrawny asthmatic' climbed the world's mountains

Extensive parkland with a mosaic of forest patches and subalpine meadow communities extends from 1, 500 - 2, 000 meters above sea level.

UNESCO: Biosphere Reserve Information

The western slopes (below 1, 200 meters above sea level) are dominated by douglas fir (Pseudotsuga menziesii) and western hemlock (Tsuga heterophylla).

UNESCO: Biosphere Reserve Information

Visit rice terraces that soar up to 3, 000 meters above sea level.

WSJ: Only in...Yunnan

The company has also looked at the offshore application of the kites to extract energy from the wind flows blowing between 200 and 800 meters above sea level.

FORBES: Italy's KITEnergy Converts High Altitude Winds to Electricity

The telescope, which is due to be completed by 2012, will consist of 66 radio antennae spread across the Llano de Chajnantor plateau, 5, 000 meters above sea level.

CNN: Telescope set to reveal 'Big Bang'

The problem is that on the Carteret Islands, a horseshoe shaped scatter of small islands around a central lagoon, nowhere is more than 1.2 meters above sea level.

CNN: Drowning islands warn of future perils for 'environmental refugees'

It is currently making its first pass down with a 12.5-inch diameter hole to the roof of the 50-square-meter (500-square-foot) refuge at Level 100 (100 meters above sea level).

CNN: STORY HIGHLIGHTS

The Rig 421 oil drill, so-called Plan C, is currently at 265 meters and en route to the roof of the tunnel at Level 150 (150 meters above sea level).

CNN: STORY HIGHLIGHTS