As far as I can remember, since I was 6 or 7 years old, and not really knowing exactly how, (I guess it was because of the interest I���ve always had in Astrophysics), that my life started centering around the UFO phenomena. As well as anyone with a deep interest on this kind of subject, I���ve always dreamed of having a true UFO sighting experience, although this was something I was doubtfully sure of, until something happened on the month of August 2013. One day I went to meet with a Chinese colleague of mine to this hotel where he was staying at in downtown La Paz. During the morning hours, we stayed in his room talking a bit about everything, and as the TV was on we started watching a rerun of the UFO Hunters series on the History Channel, while from time to time I was translating to him from Spanish to Chinese the most relevant and interesting of the contents that were discussed about the UFO phenomena. At around 5:00 in the afternoon, we took a taxi straight to the airport to change the departure date of our flight to Colombia. At around 08:00 in the evening the same day, we took another taxi from the airport back to downtown La Paz, riding down a quite long and winding highway, which links the El Alto (City) International Airport located at an altitude of 4100 m.a.s.l., with the city of La Paz located on a very large valley area at an average altitude of 3.850 m.a.s.l. Surrounding the upper part of the La Paz city valley, there is a large mountainous chain that is part of the Andes Cordillera, which during moonless nights cannot be seen because of the height and the distance they are located at. The only thing that can be seen on one of these mountains at nighttime, are 3 quite bright yellow lights that are arranged in a left to right diagonal array, the ones which during nighttime seem to be suspended in the night sky. In fact, the previous year in 2012, as I was making my way back from the airport at similar nighttime hours, for the first time I noticed those 3 bright yellow lights suspended on the left side of the sky over the valley. Thinking that those possibly were 3 UFOs suspended in close formation, I asked the taxi driver what those lights were all about, and to my disappointment he told me those were the 3 main lights of a water reservoir that channels the water from the melting ice caps from the surrounding mountain tops and used as a main water supply for the city of La Paz down the rest of the valley area. While remembering all that, and after discussing about the UFO topic during the morning hours, I was there watching again those bright yellow lights of the water reservoir that evening, and suddenly I decided to play a joke to my Chinese workmate, making him believe that those reservoir lights were 3 UFOs suspended in close formation, and see what kind of reaction I could get out of him, just for the sake of my own pleasure. I ended up feeling very satisfied finding out that my Chinese workmate reacted in awe-striking amazement thinking that those lights were real UFOs, while I was doing my best effort not to laugh at him loudly and making him find out it was a joke. While this was happening, I Looked to the right side over the same mountain range, and suddenly saw 3 other bright yellow lights that were also arranged in exactly the same left to right diagonal array formation having exactly the same altitude and distance as the water reservoir lights had!; (possibly might have been apparent altitude and distance that coincided with the reservoir lights). Now, those newly discovered lights were something I have never ever seen or known of before, and starting to feel a strange sensation inside of me, I fixed my sight on those 3 lights and noticed that they were around five times bigger than the water reservoir lights. Those strange lights kept their formation and position for around 3 minutes, and then they suddenly changed their position to a perfectly horizontal one, keeping their new position and distance for around 2 more minutes. From time to time, I could not see those lights because of the trees and houses set on along the winding highway, but as we were driving along, I noticed that those light were approaching more and more towards our direction, as if knowing that I was observing them. Then I pointed out to those lights and I asked the taxi driver what those lights could be, and after him almost hardly looking at them, told me that it was just a another airplane making its way to the airport. It took around 5 minutes for those 3 lights to fly from their initial location to a place close to where we were, which I guess was an approximate distance of about 20 km, which tells me that those light were flying at a speed of an airplane. As those light were just about over the highway, the lights changed their former horizontal array to such a way that I ended up seeing a perfectly hexagonal array of 6 yellow bright lights with a twice as big red bright light located in the middle of the hexagonal formation! To my surprise, I found out that instead of 6 + 1 separate lights/objects flying in hexagonal formation, those where the lights of one single black hexagonal UFO, which I guess was about 20 to 25 meters in diameter suddenly flying at a much slower speed above us heading to El Alto City were the airport is, at an altitude by then of about 30 meters from the highway, making no noise whatsoever! I was so amazed watching this object hat I kept myself quiet without saying a single word to my Chinese workmate, until the object flew past by and disappeared over the high plateau of El Alto City. I finally don���t know why this sighting was never shown on the news or talked about by anyone else being a fact to me that it really happened and we were altogether 3 eyewitnesses to it! As this is the first UFO sighting experience I���ve had till now, after I file in this report, I will further analyze and estimate more accurately the initial distance and altitude that the UFO had from the location of the highway where our taxi was running at and the resulting speed the UFO flew at, as well as other details of the more accurate dimensions of the object, etc. I am willing to answer any questions that you might have in the most sincere and accurate way I can. By the way, I once remember watching a MUFON tv program about a guy near Philadelphia also saw an hexagonal-shaped UFO flying near his house during a rainy thunderstorm evening��� Could you please provide me with any most detailed information about this peculiar hexagonal-shaped UFO that I���ve witnessed, where they come from and what kind of aliens maneuver them, etc. I will most gladly and thankfully appreciate it!