You could have downloaded Hidden Expedition: Smithsonian Castle Collector's Edition 2.0 for Mac from our software library for free. Hidden Expedition: Smithsonian Castle Collector's Edition for Mac is included in Games. The actual developer of this Mac application is Eipix Entertainment.
From the developer:
Your old buddy and H.E.L.P. operative Sam calls you in to investigate a strange anomaly at the Smithsonian Castle. You soon learn there’s more to this anomaly than meets the eye, and H.E.L.P’s reach stretches back to the Smithsonian’s historic founding. Unlock the secrets of time travel as you follow the clues into the Smithsonian Castle’s Civil War past.
You may want to check out more Mac applications, such as Hidden Expedition: Smithsonian Castle, Puppet Show - Her Cruel Collectors Edition or Hidden Expedition - Devil's Triangle, which might be related to Hidden Expedition: Smithsonian Castle Collector's Edition.