April 1986 map of backbone sites only:

Here is the backbone as of 1 April 1986:

                                                                      olduse.net
                                                                          |
                                                                  (wormhole to 2016)
                                                                          |
  cbosgd-----------------------------------clyde---------watmath--------utzoo
    |                                        |                            |
  ihnp4-------alberta------ubc-vision       burl                        linus
    | \                        |             |                            |
    | mgnetp                uw-beaver      ulysses--------------bellcore  |
    |                          |                                        \ |
    |                      tektronix-----------------------------------decvax
    |                          |                                        / |
  qantel---------------------\ | /---------oliveb-----glacier-----decwrl  |
    |                         \|/                                         |
    |  kddlab----------------hplabs-------sdcrdcf                         |
    |    |                     |             |                            |
    |    |                     |          sdcsvax                         |
    |    |  (see below)       hao            |                            |
    |    | /                   |          drillsys                        |
    |    |/                    |             |                            |
    |  mcvax-----------------seismo--------gatech----------akgua---------mcnc
    |                         /|\                                         |
 lll-lcc-----lll-crg---------/ | \---------cmcl2-----------------------philabs
                               |
                             munnari      


This is the European backbone (mcvax feeds all of them):

           penet  enea   diku   unido           penet -> Finland
             |      \     |     /               enea -> Sweden
             |       \    |    /                diku -> Denmark
             |        \   |   /                 unido -> W. Germany
             |         \  |  /                  vmucnam -> France
    vmucnam--+----------mcvax------cernvax      mcvax -> Netherlands
             |         /  |  \                  cernvax -> Switzerland
             |        /   |   \                 ukc -> Great Britain
             |       /    |    \                prlb2 -> Belgium
             |      /     |     \               i2unix -> Italy
           vmars  ukc    prlb2   i2unix         vmars -> Austria

(Shout out to anon.penet.fi which penet later provided! --Joey)