1.Gustave Eiffel: he was born in 5 December 1832 and dead in 27 December 1923 at Paris, France. He was a French civil engineer and architect. His first work was The Bordeaux bridge in 1857 then after that, there were The Budapest-Nyugati station, The Maria Pia Bridge, The Eiffel Tower, The Panama Scandal, etc. But the most famous was The Eiffel Tower, he had designed it in May 1884 and finished in March 1889. This tower was the most highest tower in that time and it still survive until now.
More information:
<http://en.wikipedia.org/wiki/Gustave_Eiffel>: .Gustave Eiffel
<http://en.wikipedia.org/wiki/Eiffel_Tower> Eiffel Tower
2.Isidore of Miletus: He was a Greek architect and he was one of two main Greek architect. He was a person, who designed the church of Hagia Sophia in Constantinople, he had ommissioned to design the church from 532 to 537 A.D.
More information:
<http://en.wikipedia.org/wiki/Isidore_of_Miletus> Isidore of Miletus
<http://en.wikipedia.org/wiki/Hagia_Sophia> Hagia Sophia
Engineering - Steven 