Rav Aharon Kotler (1891 - November 29, 1962) is the founder of the Beis Medrash Govoha in Lakewood, New Jersey. His life mission was to plant a vibrant, Torah Judaism in America. He started his yeshiva with just three students, and by the time he passed away, there were 100's of students - and today there are literally thousands and thousands of students in his yeshiva, one of the largest in the world.
Rav Moshe Feinstein (March 3, 1895 - March 23, 1986) was Rosh Yeshivah of Mesivtha Tifereth Jerusalem and its resident branch, the Yeshivah of Staten Island. His study table in the Beis Medrash was the address of queries coming from all four corners of the earth. He was the court of last resort for virtually all the world's leading halachic authorities.
You may be interested in these other pictures of Rav Kotler and Rav Feinstein: