Martian base concept by Janek Kozicki & Joanna Kozicka

Polish engineers/architects Janek Kozicki & Joanna Kozicka has long been working for an architectural design proposal for a Martian base after NASA (or SpaceX) will land humans on Mars for the 1st time. They call it a stage 2 and stage 3 Martian bases (stage 1 - 1st landing base; stage 2 - a small permanent Martian base; stage 3 - small Martian settlement; stage 4 - Martian cities).

Stage 2 Martian base by Janek Kozicki [PDF of the concept here]

More about the concept here.

Stage 3 Martian settlement by Joanna Kozicka

More about the concept here.