| 100% | SNUPPY | 6 | Afghan hound, the world's first cloned dog |
| 47% | DOLLY | 5 | World's first cloned sheep |
| 47% | SPUTNIK | 7 | The world's first constructed satellite |
| 46% | HAITI | 5 | The world's first Black-led republic |
| 45% | CHIHUAHUA | 9 | The world's smallest dog breed |
| 43% | LONDON | 6 | Site of the world's first subway |
| 43% | NAPLES | 6 | Site of the world's first pizzeria |
| 43% | YELLOWSTONE | 11 | The world's first national park, located in Wyoming, Montana, and Idaho |
| 42% | HATH | 4 | Verb in the world's first telegraph message |
| 42% | SEIKO | 5 | Maker of the world's first quartz watch |
| 42% | NEWHAVEN | 8 | City with the world's first telephone directory (1878) |
| 42% | NIHAO | 5 | "Hello," in the world's most common first language |
| 42% | TELETHON | 8 | Milton Berle hosted the world's first one |
| 42% | SMALLPOX | 8 | Disease eradicated by the world's first vaccine |
| 41% | BOSTON | 6 | Site of the world's first city marathon in 1897 |
| 41% | MERCEDESBENZ | 12 | Maker of the world's first diesel-powered passenger car |
| 40% | MANNHEIM | 8 | Where Karl Benz debuted the world's first auto |
| 40% | RCA | 3 | Co. that launched the world's first communications satellite |
| 40% | OWEN | 4 | ___ Hurcum, the world's first openly nonbinary mayor |
| 40% | ACE | 3 | ___ the Bat-Hound, Batman's pet dog from DC Comics who first appeared in 1955 |
| 40% | UCLA | 4 | SoCal school where the world's first internet transmission was made |
| 40% | LOUISE | 6 | __ Brown, the world's first IVF baby, born in 1978 |
| 39% | TULIP | 5 | Flower that caused the world's first economic bubble in the 1630s |
| 39% | OPEL | 4 | Automotive company that conducted the world's first rocket-powered flights |
| 38% | NINE | 4 | Cost in dollars of the world's first TV ad in 1941 |
| 38% | FUN | 3 | First Across word in the world's first crossword |
| 38% | TULIP | 5 | Flower that created the world's first speculative bubble, during the Dutch Golden Age |
| 38% | FUN | 3 | First word across in the world's first crossword (1913) |
| 38% | BIGMAMATHORNTON | 15 | Singer who was the first to record “Hound Dog” |
| 38% | GIA | 3 | ___ Carangi, considered to be the world's first supermodel |