title: How to merge many VRT file into one
body: <p>I have many VRT files generated using <strong>gdal_translate</strong> originally for adjacent images. </p>
  
  <p>Is there away to merge all those VRT file into one VRT file so that when I run <strong>gdal2tiles.py</strong> I only need to give it this one composite VRT file?</p>
  
  <p>I thought first gdal_wrap will do the trick, but it turn out that gdal_wrap images into one single image.. However, I dont want to merge images, I would like to merge VRT file.    </p>