A.k.a. the Cleopatra you're thinking of. Cleopatra VII Thea Philopatornote was the last Pharaoh of Ancient Egypt, at different points ruling jointly with her father, brother, other brother, and son, though with the latter three, she was clearly in charge and only using them to bolster her credibility as a female ruler. The Ptolemaic dynasty Cleopatra descended from was actually Greek; after the death of Alexander the Great, his empire was divided up by three generals, and Ptolemy I Soter got Egypt. Cleopatra was actually the first of her dynasty to bother learning Egyptian, and presented herself to her kingdom as a reincarnation of the goddess Isis. The identity of Cleopatra's mother is uncertain. Born the third child of Pharaoh Ptolemy XII Auletes, Auletes lost his grip on his kingdom due to corruption and the loss of of Cyprus and Cyrenaica. In a desperate bid to regain control, he fled and begged Rome for money and troops to help him regain his throne. Cleopatra's two older sisters, Cleopatra VI Tryphaena and Berenice IV, seized power at this time — first Cleopatra VI, then Berenice upon her mysterious death. Whether or not Cleopatra VII accompanied her father to Rome or remained in Egypt is debatable; she isn't really a concern in the contemporary records of either place. The reason this is even a question is because some accounts describe her as meeting Marc Antony around this age, while others assert she met him as an adult. What is certain is that Auletes eventually was able to secure the troops and money, and that Berenice was imprisoned and executed for her disloyalty. Cleopatra was now fourteen, the eldest of her remaining siblings, and thus the one with the best chance of keeping a hold on the throne should their father die. He elevated her to joint ruler at this point, though it's unlikely she had much power. In his will, four years later, he decreed that 18-year-old Cleopatra would rule jointly with her ten-year-old brother, Ptolemy XIII. She married him according to Egyptian custom, which the Ptolemies adopted for whatever reason, but refused to share power with him. Eventually, she progressed to leaving his name off official documents and his face off the coinage. This was just another complication on top of widespread famine and the Nile not flooding enough to irrigate crops. Around this time, Cleopatra ran foul of the Gabiniani, troops left behind when her father was restored to power. They killed the sons of the Roman governor of Syria, she handed them over in chains, and they didn't forget that. She was exiled when they joined with a cabal of courtiers and had Ptolemy placed on the throne as sole ruler. The teenage Ptolemy and his advisers made a grave mistake, however, when they executed the fleeing Roman consular Pompey, son-in-law and long-term rival of Gaius Julius Caesar. Upon hearing of the death, Caesar promptly took control of Egypt and declared himself the mediator between Ptolemy and Cleopatra. Cleopatra saw her chance and, legend has it, had herself smuggled to Caesar inside a rolled-up carpet. They had an affair, with Cleopatra giving birth to his son, Caesarion, or "Little Caesar." End result was that Caesar decided not to annex Egypt, and settled that Cleopatra and her brother were to be reconciled. Cleopatra would have preferred for Caesar to name their son his heir (which was illegal under Roman law, as Caesarion was not a Roman citizen) and to rule jointly with him after Caesar left, but Caesar refused. This led to a civil war in Alexandria, and, possibly, the burning of the famous Alexandria library. Caesar eventually got things under control, but Ptolemy drowned when his armor weighed him down too much. Cleopatra was promptly married to their younger brother, and he became her co-ruler. Her younger sister, Arsinoe, was taken to Rome by Caesar and executed. After the assassination of Caesar, Cleopatra insinuated herself into the newly formed government among Caesar's three heirs: de jure successor Octavius, and Caesar's top generals Mark Antony and Marcus Lepidus. Antony was given reign over the Eastern provinces (such as Egypt) and Cleo ensured her place in the new government by becoming Antony's lover and mother of three of his children (which was a shock to Antony's wife, Octavia, who was also Octavius' sister). When civil war broke out between Octavius and Antony some ten years later, Cleopatra was the principal military force backing Antony's cause (the official declaration of war was against Cleopatra, not Antony), but it was for naught. Cleo and Antony's combined forces were no match for Octavius, and after losing the Battle of Actium, the two of them escaped back to Egypt where they committed suicide, Cleo by allowing herself to be bitten by an asp, if legend is to be believed. Egypt was fully absorbed into Rome, Octavius officially changed his name to Augustus, and the line of Pharaohs was permanently disbanded. Egypt wouldn't know independence from Rome until six centuries later with the conquest by the Muslim Arabs.
Tropes as portrayed in fiction:
- Beam Me Up, Scotty!: Modern perception of Cleopatra has been distorted quite a lot by her most famous film - the real life Cleopatra would not have worn the bizarre headdresses and hair accessories that Elizabeth Taylor wore (she preferred the simple diadem worn by Hellenistic monarchs), and did not have bobbed hair.
- Gag Nose: This is usually how her nose is depicted in comic strips and cartoons. In the Asterix franchise it is drawn as a pointy triangle.
- Historical Beauty Update: There's no doubting that she was a phenomenally sexy woman, but she definitely did not look a thing like Elizabeth Taylor. In fact, many contemporaries of Cleopatra noted that she was rather plain-looking, all things considered, but that it was her charm, charisma, sense of humor, and intelligence which attracted so many powerful men to her side.
- Inverted by Cleopatra herself, who made herself look a lot uglier in portraits - see Lady Looks Like a Dude.
- Lady Looks Like a Dude: There are two kinds of ancient portrait of Cleopatra - ones in which she looks like the epitome of Greek femininity, and the ones where she looks like a cross-dresser. The latter was to stress her links to her predecessors as king, imitate images of Roman consuls, and to show herself as having the heart and stomach of a king.
- Race Lift: The real Cleo was a descendant of the Greek Ptolemaic family (who tended to be incestuous), but she is popularly imagined either with Raven Hair, Ivory Skin, or as a black woman, depending on the artist.
Cleopatra in fiction:
- She's one of the protagonists in William Shakespeare's play Antony and Cleopatra.
- George Bernard Shaw's play, Caesar and Cleopatra depicts Caesar's time in Egypt and his relationship with Cleopatra. In the 1945 film adaptation, she's played by Vivien Leigh. This adaptation depicts their history very loosely, with much timeline muddling and mischaracterization. For example, the play and film depict Cleo meeting Caesar when she is a young and timid girl, incapable of standing up to even her handmaiden. However by this point in history, Cleo would have already been ruling Egypt all by herself for some time, having bullied her younger brother into almost complete obscurity some years before.
- The 1963 film Cleopatra with Elizabeth Taylor is proably how she lives on in the imagination of most people. Taylor's famous bobcut, headdress, and elaborate gowns (the film holds the world record for most costume changes by a single actress) are all so ingrained in popular culture that they are nearly impossible to escape in modern depictions of the Pharaoh.
- Inspired a catchy jazz song, Le nez de Cléopâtre (1938) (Cleopatra's nose) by Ray Ventura. 
- The Astérix album Asterix and Cleopatra introduced her as a recurring character in the Asterix franchise. In the 2002 film based on the album Asterix & Obelix: Mission Cleopatra, she's portrayed by Monica Bellucci.
- Also battled against Marilyn Monroe in Epic Rap Battles of History.
- Plays an important role in the second series of Rome where she has sex with Titus Pullo. She's played by Lyndsey Marshal.
- Shows up in Time Squad where she demolishes the pyramids so she can build a mall(for herself only).
- One of The Royal Diaries features her, centering around her following her father to Rome and her first meeting with Marc Antony.
- She was portrayed by Amanda Barrie in Carry On Cleo.
- She was portrayed by Leonor Varela in a 1999 miniseries with Timothy Dalton as Julius Caesar and Billy Zane as Marc Anthony.