Ignatius Yakovlevich Stelletskii (Russian: Игнатий Яковлевич Стеллецкий; February 3, 1878 - November 11, 1949) was a Russian and Soviet archaeologist, historian, and researcher of the tunnels of Moscow. He was known to make searches for the library of Ivan the Terrible all throughout his life.[1] He is considered to be the founder of the Urban exploration movement in Russia.