Its simplicity is one of a kind and it takes my breath when I realize that this little drawing is actually the internets Big Bang point of origin. It shows the first node on the ARPANET at the University California Los Angeles (UCLA) on the 2nd September 1969. The diagram is taken from Casting the Net: From ARPANET to INTERNET and Beyond by Peter H. Salus and was drawn by Alex McKinzie who worked for BBN.
New maps and ongoing research can be found (on the internet of course): for example here, here and here.
Related: It's nature... but not as we know it | Periodic Table of the Internet | World Mapper