THEN: The Great Wall Of China is the only man-made structure visible from space.
NOW: Many man-made places are visible from space.
Technically, this wasn't ever a solid "truth" — just a fact third-graders ubiquitously included in their class reports and diorama presentations. In fact, rumors that you can see the landmark, not only from a spaceship, but all the way from the moon, date back as far as 1938.
In 2003 though, the first Chinese astronaut finally shattered the myth.
Other photos surfaced here and there. The consensus became that you can, indeed, catch glimpses of the Wall but only under the right conditions (snow on the structure) or with a zoom-capable camera. You can also see the lights of large cities — and major roadways and bridges and airports and dams and reservoirs.
The moon factoid, however, is totally wrong.
"The only thing you can see from the Moon is a beautiful sphere, mostly white, some blue and patches of yellow, and every once in a while some green vegetation," Apollo 12 astronaut Alan Bean told NASA. "No man-made object is visible at this scale."
To further clarify, people probably mean these structures are visible from satellites orbiting Earth — but that's not actual space.
THEN: Five (or three) kingdoms of classification exist.
NOW: There might be as many as eight kingdoms.
Depending when you grew up, your middle school science teacher probably lectured about three main kingdoms of life — animals, plants, and bacteria (monera) — or five, including fungi and protists, too.
Either way, we've expanded our classification of life since then.
The more species we find and analyze, the more complex labeling life becomes. In addition to the five kingdoms above, we now know of archaea, previously thrown under monera. Archaea superficially look like other one-celled organisms called eubacteria, but they're completely different.
Even larger systems exist which further divide eubacteria into two more kingdoms or separate chromista from all the other protists.
In the U.S., however, we stick with six: plants, animals, protists, fungi, archaebacteria, and eubacteria.
Christina Sterbenz contributed to a previous version of this story