It started with the usual "I've explored more drains than you." stuff with some guy who had explored fifty. There were of course lots of people who had explored more than that. I was staying silent on that until some one finally started bugging me about how many I had explored.
"Oh, plenty of people have explored me drains than me no doubt" I replied.
"So how many have you explored?" Asked Mr 50 drains.
"Oh, only about a hundred and fifty to two hundred." I replied, then paused. "In twenty one countries" I added.
Mr 50 drains just looked at me.
"The ones in Sao Paulo were bigger than Melbourne but you had to wear waders because they were so polluted." I finished.

Then some one got on to the oldest drain they had explored and the Tank Stream in Sydney came up. Eventually some one noticed I was quiet and grinning again.
"Okay Panic, I assume you've explored something older than the Tank Stream then?"
"Yeah, I explored this one in Rome called the Maximus Glochea or something like that."
"How old was it?" Some one asked.
"I think it was there before Jesus did his walking on water trick." I replied. "Okay strictly speaking it was a sewer in it's time, but it is a drain now."
"So that's like 2000 years old?" Some one asked.
"Yeah, at least." I replied. Then we chatted about similarities between it and the Tank Stream.
Finally the conversation moved on to the oldest topside we'd explored. Mr 50 Drains asked me straight up. "I suppose you've explore something really old?"
"Well I suppose the pyramids are topside, how old are they?" I asked.
"You bastard." Mr 50 drains said.
"Yep." I replied.

Mr 50 drains has now explored over 250 including about 80 in Europe. My turn to be jealous.