This image is of Mariscal Sucre International Airport near Quito, Ecuador. (Official site / in English)
What is the purpose of the loop in the taxiway plainly visible in this image?
From Google Earth (with the contrast punched up a bit)
Addendum
To respond to the comments to jwzumwalt's answer, I really don't think the hills and mountains to the north of this airport are an operational concern. See below image:
Source plus my copy-and-paste extras
The airport's elevation is 7900 feet (verified by Skyvector), the first ridge in jwzumwalt's 2nd image is 6.4 miles distant from the north end of the runway and lower in elevation, and the second ridge is 8 miles distant but only 500 feet higher. Distances verified by Google Maps.
If an aircraft can't comfortably clear a ridge 500 ft above the airfield in eight miles, well then that's a whole other issue. :-)
But, I do like jwzumwalt's answer. Thanks!