To tell the truth, I did not know about St. Tekla until a cold night last November when we arrived at the Orthodox Convent in Maaloula, Syria. Tekla was converted to Christianity by St. Paul and later sought refuge in the desert. Her legend says that a rock opened up and she was able to hide.
There is a mysterious spring in the overhead rock that mists water down to a carved stone basin. The misting water is very fine and is said to bring blessings.
P.S., Tekla is spelled in a variety of ways, including Thecla and Thekla. For more information, go here or here.