Free project software (equivalent to MS Project)

[Chronos-X]

Hello!

I'm aware there are free Office suites that basically mimic MS products in everything but the name - the various open office suites etc. Is there an equivalent program for MS Project that we can use as a project management tool with Gantt charts etc.?

 

[Chronos-X]

OK, how about a Visio equivalent - and which of these can open Project's own files?