For example, it is not possible to return to the past without changing the past in some way; nor is it possible to change the future based on information from the future.  Doctor Who realized early on that changes to history were hazardous, and avoided them assiduously. Movies built on a time travel theme frequently become dissatisfying when the thread of time is closely examined.  In Millennium, once the era in which the time machine exists is destroyed, aren’t all of those rescued survivors returned to their own times?  In The Twelve Monkeys, doesn’t it appear that the disaster which the main character was to prevent

would not have happened had he not interfered?  In Timecop, would any of that have happened had it not happened?  Even the venerable StarTrek has created numerous anomalies which it has failed to resolve.  Pasts which are dependent upon futures dependent upon those pasts should make us cringe.  However, from time to time something works.  This web page will attempt to examine some of the best examples of these, beginning with Temporal Anomalies in Popular Time Travel Movies.