In 1958, he exhibited in the Eduard Loeb Gallery in Paris and was invited to take part in the Art du XXI Siècle which was held in Charleroi, Belgium.
Serrano's abstract introspection reached its zenith with the series Rhythms in Space, dynamic compositions constructed from stainless steel rods.
In 1959, while taking part in one of Pierre Schaeffer's experimental music projects, Serrano presented his working models for these series, as well as the first Burning of an object entitled The Dis-occupation of the Space or the Presence of the Absence in the Galleria del Disegno in Milan, Italy.
The reputation that he had by now firmly established lead him to be selected to take part in the New Spanish Painting and Sculpture exhibition that was on show for two years at first in MOMA in New York and later in Washington, Chicago and New Hampshire.
Pablo Serrano was invited in 1961 to The Pittsburg International in the Carnegie Institute in the United States, and to the II Exposition Internationale de Sculpture Contemporaine in the Rodin Museum in Paris.
He entered 23 pieces for the XXXI International Biennial in Venice in 1962, only to find himself a mere one vote short of the First Prize for Sculpture, which was to be won by Alberto Giacometti.
Concurrently, and in keeping with the aesthetic and philosophical line he had started at the beginning of the decade, he produced Men with Door, a logical continuation of his earlier Men-Vault.
Serrano exhibited pieces from these last series at the Juana Mordó Gallery in Madrid, as well as their original plaster versions at the Guggenheim Museum in New York.