Q. What Brocho does one say if any when seeing first time Niagara Falls?
A. Horav Shlomo Miller's Shlit'a opinion is than one can recite 'Ose Maase Bereishis.' However, if one has recited that blessing within thirty days, as in the case of seeing the sea, one should not repeat it with Hashem's name.
Rabbi A. Bartfeld as advised by Horav Shlomo Miller Shlit'a and Horav Aharon Miller Shlit'a