What made President Nixon's trip to Red China so significant?

Because it was to improve U. S. relations with communist china after the tension from the cold war.

First US visit by a sitting president to China since it becoming a Communist country.

This represented a thawing in Cold War thinking that created two separate spheres in the world. Nixon began US efforts to improve relations between the US and China. He also believed it was time for the US to begin policies reducing nuclear weapons development and create trade agreements with countries cut off by the Cold War.