Lake Mennar

Lake Mennar is one of the few places in the world where the blue dragonflight can be found outside of Northrend. The only comparable place is Mazthoril in Winterspring. Although most of the region on all sides of the lake is inhabited by dragonspawn, the actual lake itself is free from danger and can provide solace and refreshment to those who are brave enough to get through the perimeter dragonkin.

After the Cataclysm, Malynea Skyreaver provides some insight into the lake's origins:

After the Fourth War, Zekhan and Rexxar visited the place and mentioned in his report that the blue dragons were still present in the area and concluded that this lake remains a special place for them. Malynea Skyreaver then explained that what is drawing them is a Sarcen Stone