On paper, the concept of a portrait gallery sounds like Field Trip Hell. But actually, you’ll be surprised how the best works capture the sparkle of life behind history’s most charismatic shapers. Here, the names from your high school textbook flower into flesh-and-blood people, and the accompanying biographies are so sublimely evocative (Samuel Johnson is described as “massive, ungainly, plagued with nervous tics”) that subjects come alive.

The ancient kings and queens have the most heft, partly because it’s hard to wrap your brain around the fact that in many cases, the actual people posed in the same room as these very canvases. One of the most instantly recognizable paintings is the Ditchley portrait of Elizabeth I (room 2), in which the queen’s jeweled gown spreads like wings and Her Majesty firmly glares at the viewer under stormy skies. Right away, it becomes clear that many artists are slyly commenting on the disposition of their sitters. The troublesome Henry VIII is shown in several likenesses. One is a delicate 1537 paper cartoon by Hans Holbein the Younger (for a mural at Whitehall—a rare survivor from that palace), in which the king suspiciously peers with flinty grey eyes—hinting at a shiftiness that His Majesty probably couldn’t recognize in his own likeness, but that all who knew him feared (room 1). One painting of King Edward VI, painted when he was 9, is executed in a distorted perspective (called anamorphosis) that requires it to be viewed from a hole on the right side of its case (room 1). In 2014, the 1630s self-portrait of Van Dyck (room 15) was recovered from four centuries of private ownership for £10 million in patron donations of £1 to £20,000—the world’s most valuable selfie. You’ll also find George Washington (he was born an Englishman, after all), and one of the only authoritative images of Captain James Cook (room 14), who was so pivotal in colonial expansion. In room 12, look for the newly acquired Chevalier D’Eon, a male diplomat and fencing champion who lived as a woman in the late 1700s, and in room 18, for the sketch of Jane Austen by her sister Cassandra—friends said it stank. The Brontë Sisters appear together in an 1834 portrait found folded atop a cupboard in 1914; their brother Patrick, the artist, was painted out but his ghostly image is eerily re-appearing (room 24).

Fortunately, the portraits don’t stop when cameras were invented. The image of Margaret Thatcher, demure in a chair, makes the Iron Lady look sweet as your granny (room 32); she is faced down by Paul Emsley’s warm oil-on-canvas of Catherine, HRH The Duchess of Cambridge (2012). The bust of artist Marc Quinn is formed by eight pints of his frozen blood (room 38). In contrast, a 1950 sitting-room portrait of Queen Elizabeth II with her parents, King George VI and the Queen Mum, mines Rockwell-esque, just-us-folks imagery (Mum’s about to pour tea, Dad’s smoking) to make the Royal Family seem as normal and as middle-class as the Cleavers (room 31). Modern portraits tend to change often because there’s simply not enough room to show everything. Just about everything can be printed as a poster in the gift shop.

Take the escalator to the top and work your way down over about 2 hours. The oldest works (Tudors, Jacobeans, Elizabethans) come first, and you’ll progress forward in time—adding photography when canvas fatigue sets in. Frankly, it helps to know a little history so these pictures ring some bells, so consider visiting near the end of your trip, when many of these names will be fresh in your mind from your tours. The £3 audio guide starts out dull, but by the end, it uses archival recordings, which is cool, and there’s a $2 smartphone app of the highlights. Bring kids; the desk lends free discovery trails for them.

Late Shift evenings (Thurs, Fri 6–9pm), programmed with DJs, talks, live music, and drawing sessions, are fun. Also consider the pre-theater menu (£18 for two courses, £21 for three) served from 5:30 to 6:30pm in the rooftop Portrait Restaurant, which has a breathtaking view taking in Nelson’s Column and Big Ben’s tower (; [tel] 020/7312-2490).