Bosnia marks 20 years since princess dianas visit

I think there may be some confusion here. Princess Diana did not visit Bosnia. It's possible that you may be thinking of another country or event.

However, Bosnia and Herzegovina has indeed marked significant anniversaries and milestones in recent years. For example, in 2012, Bosnia and Herzegovina marked the 20th anniversary of the Srebrenica genocide, in which over 8,000 Bosniak (Bosnian Muslim) men and boys were killed by Bosnian Serb forces during the Bosnian War.

If you could provide more context or clarify what you are referring to, I'd be happy to try and help you further.