What is associated with: at its peak this network endorsed by dionne warwick had 1500 mediums answering phones giving advice?

Based on the clue 'at its northern end this colorful sea branches int...', what is the answer? Based on the clue 'at its opening this nyc building was the largest m...', what is the answer? Based on the clue 'at its peak attila the huns empire ranged from the...', what is the answer? Based on the clue 'at its peak the ottoman empire stretched as far so...', what is the answer? Based on the clue 'at its peak this standard oilers personal fortune ...', what is the answer? What is associated with: at its premiere in nyc in 1924 this composition was part of a concert billed as an experiment… Based on the clue 'at its standard mass it puts the red in red firewo...', what is the answer? What is associated with: at its widest north south point this large sea stretches 1000 miles from libya in africa to cr…