Ori Supergate from the Stargate Series.

The model is quite big (40cm across), so you can fit almost any Stargate ship through it.

The model is super easy to assemble, with only three different parts. 12x Gate parts (6 for each side), 12x Pins to hold gate sides together, and 2x Stands.

In case you want to put it on your wall, you need to print only the first plate (6x Gate parts).