This is what happened in Sindh city in Pakistan after the major floods which hit this city in 2010th. at the first look at these trees you'll see a spiders nets and these are really belongs to spiders that live in this area. Then what happens and why this phenomena doesn't appear before the flood. The answer becomes in your mind isn't it? :) .
So this is really an amazing phenomena. The spiders that were live at the ground before the flood now crawling and forced to climb the trees as you see the trees are woven a remarkable large number of spiders webs. The most amazing thing was happened because the spiders webs, After the flood a lot of houses were destroyed so so many diseases appeared for example the Malaria. And here comes the spiders webs benefits. The large number of spiders that have woven a net around the whole tree reduced the number of Malaria .
Go ahead and watch the rest of the photo.