According to 1 Kings 11:7 in the Bible, Solomon built a high place for "Chemosh, the abomination of Moab, and Molech, the abomination of the Ammonites." Chemosh was the chief god of the Moabites, while Molech was a god associated with fire and was thought to have been worshipped by sacrificing children in a ritual of burning.
Solomon's association with these false gods was a clear breach of his covenant with the Lord, and his actions were condemned by the biblical writers. The building of the high place for Chemosh and Molech was a result of the influence of Solomon's foreign wives, who brought their own religious practices to the palace and turned Solomon's heart away from the Lord. This was one of the reasons why the Lord decided to divide Solomon's kingdom into two parts after his death, and it led to the rise of the kingdoms of Israel and Judah.