http://natgeotvsales.com/DownloadPage.aspx?Type=0&Id=1

I would like to download all the files Id=1 to Id=10000 (not sure how many
there are though). 

I have seen on the forum, people who want to download only .doc, .pdf, or
such, but my URL does not have any .-ending. 

So how can I do this?