One of the early game evil kings states that he can turn the five-story building they are in to ashes if he so desired. This is an office building that was five stories tall so let's go.
Storey is 4.3 m so 603.87 * 4.3 = 2596.64 m^3.
For a building like this I will assume 80% hollowness for the inside, so volume of stone would be 519.33 m^3. Density of concrete is 2400 kg/m^3 so mass is 1246392 kg.
Melting Point of Concrete = 1450 C
Typical Temperature = 16 C
Specific Heat of Concrete = 880 J/(kg*K) (Source is apparently Assaltwaffle)
Specific Heat Energy = (1450 - 16) * 880 * 1246392 = 1.573e12 Joules, or Multi-City Block level.
Chairman Evil King Burns a Building: 375.96 Tons of TNT, Multi-City Block level