The Parts That Remain

Photo by Dan Brekwoldt

I caught myself thinking yesterday about all the historic landmarks and monuments around the world... places like Machu Picchu, or the Parthenon, or the Taj Mahal.. there are countless others as well ( here is a page on another site detailing ten of them).  
People today trek around the world to see these places, but what makes them stand out as important? Granted, they've survived this long. For some of the oldest ones that's definitely an accomplishment on its own... but what makes them significant is that they're a window into the people who came before us... right?

With that in mind, I couldn't stop myself from wondering what will be significant 300, 500, or even 2000 years from now. We don't build the same as they did, so many things will not survive without strict attention to preservation. Where many of the important structures around the world that we venture to today were built with stone, we currently use metal and glass and wood. Metal rusts and decays, glass shatters, and wood deteriorates more quickly than either of the other two. 
We build some structures with materials like concrete, but what does that leave us with? People in the distant future might see a football stadium or something. But is that all that will remain of modern America?
And what about other countries? What will be their legacies?

I'd be interested to know what some others think on this topic. Feel free to message me with your thoughts!