The phrase "blew sky-high" typically refers to a sudden and explosive destruction of something. The antonyms for this phrase would be words that convey the idea of stability, security, and preservation. Words such as "built" and "constructed" represent the opposite of destruction, implying the creation and establishment of something. Similarly, words like "conserved" and "protected" illustrate the idea of safeguarding something from harm or loss. Other antonyms could include "assembled", "guarded", "preserved", "repaired", and "secured". These words represent a more positive and constructive approach, emphasizing the importance of saving and protecting what we hold dear.