As they looked (βλεποντες). Present active participle of βλεπω. See οταν βλεπωσιν in verse Revelation 18:10.

What city is like the great city? (τις ομοια τη πολε τη μεγαληι;). No πολις with τις, but implied. Associative instrumental case, as usual, with ομοια. "The eternal city" is eternal no longer.