I think I'll write about the catacombs. I stood in line for two hours (!) just to get in. Even though I got there before they opened. I'd checked out of my hostel that morning and was already carrying a hiking backpack. Of course, at the entrance they told me there's no way I can bring such a large bag inside, and since they don't have a coat check, they wouldn't let me in. You can buy tickets online, but everything was sold out for the next two days, and I waited too long to book. Plus, on their official website they cost twice as much as at the ticket window o.O

The thought of standing in that line again wasn't appealing. Fortunately, I managed to negotiate with the security guard that if I quickly found somewhere to stash my backpack, they'd let me back in without waiting.

A waiter from a nearby café kindly agreed to watch my things if I bought something from them later (their French onion soup was really excellent :) )

The catacombs themselves are former quarries. But in the 19th century, remains from cemeteries inside the city walls were reburied here to improve sanitary conditions in the city. 6 million skeletons (!)

It's worth hurrying. Groundwater sometimes reaches the level of the tunnels and even slightly floods the passages. The entire system is at risk.