Interesting mix of people, most of whom were chill. Always something new to discover. And they were pretty open to discussing the elephant in the room: much of everyone's collection had been looted at some point. The only notable exception to that was an AMA by a Jr. Sales Person from Harlan Berk. He got roasted.
The rest of this is just me ranting about coins.
Coins are a relatively new invention. The first recognizable coins were made in Lydia (modern day Turkey) around 600BCE. For perspective, Egypt's Old and New Kingdoms did not have standardized, metallic currency. (which is a shame - considering Egypt's art, their currency probably would have looked awesome).
Greek coinage emphasized art and sometimes local trade items. For example, if your city was famous for its horses your coins would probably feature horses.
Celtic coins often looked like their artists were eating every mushroom they could get their hands on.
Roman coins emphasized political power, and had a lasting impact on the rest of coinage in the west. For example, they standardized putting the Leader's head on the obverse, and an uplifting design on the reverse. Sometimes they'd put the Emperor's wife on the front, which is always fun. (Curiously, Canadians that I've talked to about this are obstinate that the Queen is on the back and that the Bluenose/Loon/Beaver/whatever is on the front.)
Of course China had its own monetary progression. Ant Nose Money and Spade Money, for example, preceded the round coin with square hole that has been prevalent for the past 1200-ish years. India produced some really cool square coins. Japan minted one and two "Bu" coins that were rectangular during the 1800s - and although that's stretching the definition of ancient, I think they're cool.