Performing Salah near shrines or graves allowed or not?

The city where I live has many **shrines (structures made on the graves of some religious people)** and people (both men **and women**) in large numbers (tens of thousands) visit those shrines and also offer their prayers there **(Salat)**. Is it allowed in Islam? And I guess it's answer might be related to this Hadith : > Narrated Abu Huraira: Allah's Messenger (ﷺ) said, "May Allah's curse be on the Jews for they built the places of worship at the graves of their Prophets." (source : http://sunnah.com/bukhari/8/86 ) but what does this exactly mean? places of worship.. places of worshiping whom? **ALLAH (SWT)** or the grave? Kidnly, Clarify.