The PDP-11 was DECs first 16-bit architecture, and until the VAX, the
most successful machine DEC ever built.
Arguably, it's even more successful than the VAX, since new PDP-11s are still built, while the VAX has been terminated.
Companies that currently build PDP-11s are:
and then you have software emulators, even commercial ones:
Update have a number of PDP-11s around, but currently only one is in use, and that is Magica.Update.UU.SE. A PDP-11/70 which runs RSX.
Here are some pictures of Magica.
If you need help with PDP-11s, or RSX, jump to this page.