Catching criminals like Bundy, Gacy, and Dahmer. Lots of people talk about how horrific and disgusting their crimes were and they forget that these monsters were caught. Granted, oftentimes not due to ace detective work by three letter agencies, but by regular people catching them on something mundane.

Bundy was caught after he was stopped by local police for speeding and the officer found him in a stolen vehicle. Gacy was caught after he was spotted on surveillance footage. Dahmer was found out after he solicited a potential victim who then flagged down local police officers. Hell, even Robert Pickton was caught by Canadian police after his property was raided for the suspected possession of illegal firearms.

I feel like the finding of the Rosetta Stone has to be up there. Suddenly, after thousands of years you can start to translate Egyptian hieroglyphs? That was a long wait with an amazing payoff.

Roman concrete that resisted sea water, and the missing Roanoke colony.

The lost recipe for the concrete turned out to be something we misinterpreted, and the Roanoke colony was abandoned because the settlers decided to live and mix with the natives. DNA tracing was able to connect this.

The French guy who claimed to be a missing boy in the 90s, he even lived with the crazy mother.

Nicholas Barclay, aged 13 at the time he went missing, was last seen playing basketball with his friends in his home town of San Antonio, Texas, on 13 June 1994. Barclay never made it home and has not been seen or heard from since. In 1997, Bourdin took Barclay's identity and was flown to the United States. Although Bourdin had brown eyes and a French accent, he convinced the family he was their blue-eyed son, saying he had escaped from a child [abuse] ring and the ring had altered his eye color. Bourdin lived with the family for almost five months until 6 March 1998.

The craziest part is they recently found out the brother was the m******r and mu*****d Barclay with permission of his mother, and the only reason the French guy got away with it is because the family didn't want to reveal that they knew who [unalived] Barclay.