A few days ago, I asked what you thought the photo below  was  and  promised to let you know the answer later.  You gave some great guesses, but scroll down to see what it really is:

Click on the first photo below to enlarge the photos and see these incredible Mayan Pole Flyers.  When you get back to the first photo, click on the X at the upper right to come back to this page as there are two videos at the bottom of the post. 

I first saw these Mayan Pole Flyers from Veracruz in the park in Mexico City, but a month or so ago, when I took a stroll on the malecon in Ajijic, they were performing there as well. I imagine it might have been quite a feat of engineering to get the 30-meter pole installed securely enough to support all their weight.  Here are videos of their performance. Unfortunately, you’ll have to tilt your device (or head) sideways to see it.