Short answers, pulled from the story.
Alcmene was a mortal woman in Greek mythology, the wife of Amphitryon and the mother of Heracles by the god Zeus. Her name means "strong in wrath" in Greek. She was also the daughter of Electryon, king of Tiryns and Mycenae, making her a great-granddaughter of Perseus and Andromeda.
Zeus ordered Helios, the sun god, not to rise for three days, stretching a single night to triple its length. He then visited Alcmene disguised as her husband Amphitryon, even recounting Amphitryon's military victories to convince her. Alcmene believed she was with her husband, and Heracles was conceived during that deception.
Hera, Zeus's wife, actively obstructed the birth. According to Homer's Iliad, Hera caused Eurystheus to be born prematurely while preventing Alcmene from delivering Heracles, so that Zeus's oath about a ruling child would be fulfilled by Eurystheus instead. In Ovid's version, the goddess Lucina sat with clasped hands and crossed legs for seven days and nights, using charms to block the labor, until a maid named Galanthis tricked her into breaking the spell.
Galanthis was a maid of Alcmene who tricked the goddess Lucina by falsely announcing that Alcmene had already safely delivered her child. The surprise caused Lucina to jump up and unclench her hands, breaking the spell and allowing Heracles to be born. As punishment for deceiving Lucina, Galanthis was transformed into a weasel, but she continued to live with Alcmene.
After Amphitryon died, Alcmene married Rhadamanthys, a son of Zeus, and lived with him in exile at Ocaleae in Boeotia.
Pausanias recorded that Alcmene's tomb was located near the Olympieum at Megara. According to the Megarian tradition, Alcmene died while walking from Argos to Thebes and the oracle at Delphi ruled that she should be buried at Megara, despite disagreement among the Heracleidae over whether to take her body to Argos or Thebes. The Thebans held a different tradition entirely, claiming she was transformed into a stone at death.