There’s something delightfully dramatic about how the old Greek family tree unfolds — it reads like a soap opera crossed with cosmic violence, and I love it. In the myths preserved most famously in Hesiod’s 'Theogony', Uranus (the Sky) and Gaia (the Earth) are the primordial parents. They produce a whole generation of beings: the Titans (Cronus, Rhea, Oceanus, Hyperion, Theia, Themis, Mnemosyne, Iapetus, Coeus, Crius, Phoebe, Tethys, and a few others), the monstrous Hecatoncheires (the hundred-handed ones), and the Cyclopes. So when someone asks what links Zeus’s father to Uranus and Gaia, the simple genetic line is direct — Cronus (Kronos) is a son of Uranus and Gaia.
Cronus’s story is tightly tied to that parentage. Uranus, fearful of his children, imprisoned some of them inside Gaia; Gaia, enraged, plotted with Cronus to overthrow Uranus. Cronus castrates Uranus, seizes power, and becomes the leader of the Titans — so you get this vicious passing of rule from father to son. Cronus then marries Rhea (his sister, also a child of Uranus and Gaia), and they become the parents of several Olympian gods, including Hestia, Demeter, Hera, Hades, Poseidon, and crucially Zeus. Rhea eventually hides Zeus to prevent Cronus from swallowing him (Cronus had swallowed their earlier offspring because of a prophecy), allowing Zeus to grow up and later force Cronus to disgorge his siblings and overthrow him.
So the lineage is: Uranus + Gaia → Titans (including Cronus and Rhea) → Cronus + Rhea → Zeus (and his siblings). I always find the cyclical nature fascinating — the child usurps the parent, then the child of the usurper repeats the cycle, but with different alliances and consequences. If you like tracing pedigrees, that tree branches into so many myths: the Cyclopes and Hecatoncheires’ role in helping Zeus, Aphrodite’s odd birth from Uranus’s severed parts, and Gaia’s persistent influence as prophet and instigator. If you’re into primary sources, reading 'Theogony' gives you the raw, poetic flavor of these tangled relationships and the way the Greeks explained cosmic order through family drama.