An example: 
The 18th Dynasty ended when its last three kings—Tutankhamun, Aye, and Horemheb—each died without an heir.
Think about this sentence.  First the rest of the article does not give dynasty by dynasty chronology.  Second, we are not told about the start of the 18th Dynasty or of it being anything special.  Third, how does a dynasty end when three subsequen rulers die withouth heirs?  I mean they ruled AFTER each other.  Also, why is this such a big deal, when Egypt survived it the first 2 times?