I watched "Them!" (1954), one of the first and arguably the best of the 1950s "creature features" (also predates the first Japanes Godzilla movie, by a few months, in the "radiation and giant beasties" movie stakes)
Thanks to an intelligent script, good acting and characterisation, and nice cinematography, it stands up remarkably well. Most of us have grown up seeing spoofs and mockery of the poor imitations of this film, and laughing at bad giant puppet models of monsters etc. "Them!" does indeed have some wobbly model giant ants but it's smart enough to use them VERY sparingly.
Sure it includes all the cliches of this kind of film, but it probably CREATED most of them, and to its credit it has moments of smart humour in the dialogue. Even more to its credit is that, for a 1954 film, it's refreshing that it has an attractive young female scientist who is not made the subject of any romantic sub-plot and who never becomes a damsel in distress (indeed, her looks are commented on only once, her credentials are never questioned, and she quickly and successfully deals with someone claiming "this job is too dangerous for a lady").
Rather bleak outlook at the end too.
Great classic stuff.
100% on Rotten Tomatoes, for people who think that that has any sensible meaning at all.