Does anyone know where I can download a safe, free copy of Minecraft?

[LicoriceAllsorts]

It needs to be clean and safe.
It doesn't need to be state of art. An older version would be fine.
I want to get my students to build a Greek temple.
Alternatively, does anyone know of free software which they could use to build a temple?

 

[Pizzachu]

I'm so late to this post, but Google SketchUp is an option. There is a free version that students can use.

 

[Cthulhu]

There's Minecraft Classic at https://classic.minecraft.net, a web based version. Huh, I didn't actually know that existed. I knew they had an old version of the original Minecraft (java version) around for demo purposes, but this seem to be a non-java, webgl based version with limited multiplayer support (up to 10 players).