[Right triangle ⏵ may be expanded, down triangle ⏷ to close. Button = tree pop-up. × = close pop-up.]

Terminal: run. Derivation Graphs: (left-to-right) compact / full; (top-down) full / compact.

Variants: the bombing of the city was criminal / *the bombing of the city were criminal / *the bombing of the cities were criminal / *the bombings of the city was criminal / *the bombings of the cities was criminal the bombings of the cities were criminal
Simpler: The bombing was criminal / *The bombing were criminal / The bombings were criminal / *The bombings was criminal

g [the,bombing,of,the,cities,was,criminal] [the,bombing,of,the,cities,was,criminal] [the,bombing,were,criminal] [the,bombing,were,criminal] [the,bombing,of,the,cities,were,criminal] [the,bombing,of,the,cities,were,criminal] [the,bombing,were,criminal]->[the,bombing,of,the,cities,were,criminal] [the,bombing,of,the,city,were,criminal] [the,bombing,of,the,city,were,criminal] [the,bombing,were,criminal]->[the,bombing,of,the,city,were,criminal] [the,bombings,were,criminal] [the,bombings,were,criminal] [the,bombing,were,criminal]->[the,bombings,were,criminal] [the,bombings,was,criminal] [the,bombings,was,criminal] [the,bombings,of,the,cities,was,criminal] [the,bombings,of,the,cities,was,criminal] [the,bombings,was,criminal]->[the,bombings,of,the,cities,was,criminal] [the,bombings,of,the,city,was,criminal] [the,bombings,of,the,city,was,criminal] [the,bombings,was,criminal]->[the,bombings,of,the,city,was,criminal] [the,bombings,was,criminal]->[the,bombings,were,criminal] [the,bombings,of,the,city,were,criminal] [the,bombings,of,the,city,were,criminal] [the,bombing,was,criminal] [the,bombing,was,criminal] [the,bombing,was,criminal]->[the,bombing,of,the,cities,was,criminal] [the,bombing,was,criminal]->[the,bombing,were,criminal] [the,bombing,was,criminal]->[the,bombings,was,criminal] [the,bombing,of,the,city,was,criminal] [the,bombing,of,the,city,was,criminal] [the,bombing,was,criminal]->[the,bombing,of,the,city,was,criminal] [the,bombings,were,criminal]->[the,bombings,of,the,city,were,criminal] [the,bombings,of,the,cities,were,criminal] [the,bombings,of,the,cities,were,criminal] [the,bombings,were,criminal]->[the,bombings,of,the,cities,were,criminal]

To the other core example: The bombings of the city were criminal

(Chomsky 2021), p9 excerpt. (Examples (3a-d) discussed here.)
Help: blue = parse inside. Abbr.: WS: Workspace; Initial WS: initial heads for Merge after LEX lookup.
×

Words: the bombing of the cities was criminal
Initial WS 1: criminalθ vpred:pst INFLv:sg citiesthe:case(gen) bombingthe 
WS 1: {criminalθ, citiesthe:case(gen)} vpred:pst INFLv:sg bombingthe 
WS 2: {vpred:pst, {criminalθ, citiesthe:case(gen)}} INFLv:sg bombingthe 
WS 1: {criminalθ, bombingthe} vpred:pst INFLv:sg citiesthe:case(gen) 
WS 2: {vpred:pst, {criminalθ, bombingthe}} INFLv:sg citiesthe:case(gen) 
WS 3: {INFLv:sg, {vpred:pst, {criminalθ, bombingthe}}} citiesthe:case(gen) 
WS 1: {bombingthe, {citiesthe:case(gen), {criminalθ, citiesthe:case(gen)}}} vpred:pst INFLv:sg 
WS 1: {bombingthe, citiesthe:case(gen)} criminalθ vpred:pst INFLv:sg 
WS 2: {criminalθ, {bombingthe, citiesthe:case(gen)}} vpred:pst INFLv:sg 
WS 3: {vpred:pst, {criminalθ, {bombingthe, citiesthe:case(gen)}}} INFLv:sg 
WS 4: {INFLv:sg, {vpred:pst, {criminalθ, {bombingthe, citiesthe:case(gen)}}}} 
Final WS: {C, {INFLv:sg, {vpred:pst, {criminalθ, {bombingthe, citiesthe:case(gen)}}}}} 
INT/EXT: {C, {INFLv:sg, {vpred:pst, {criminalθ, {bombingthe, citiesthe:case(gen)}}}}}
EXT: the bombing of the cities 3sg pst be criminal
Spellout: the bombing of the cities was criminal
Parse found: the bombing of the cities 3sg pst be criminal
EXT: there 3sg pst be criminal the bombing of the cities
Spellout: there was criminal the bombing of the cities
Blocked: inconsistent with input!
Final WS: {CQ:aux(sg,pst,be), {INFLv:sg, {vpred:pst, {criminalθ, {bombingthe, citiesthe:case(gen)}}}}} 
INT/EXT: {CQ:aux(sg,pst,be), {INFLv:sg, {vpred:pst, {criminalθ, {bombingthe, citiesthe:case(gen)}}}}}
EXT: sg pst be →→ the bombing of the cities 3sg pst be criminal
Spellout: 3sg pst be the bombing of the cities criminal
Spellout: was the bombing of the cities criminal
Blocked: inconsistent with input!
EXT: sg pst be →→ there 3sg pst be criminal the bombing of the cities
Spellout: 3sg pst be there criminal the bombing of the cities
Spellout: was there criminal the bombing of the cities
Blocked: inconsistent with input!