The Newyorkology blog just listed one of the latest additions to the Obscura Day 2011 line-up: a catacombs tour of New York City’s Green-Wood Cemetery. Who knew (I didn’t) that the cemetery’s “winding paths amid shady oak trees by ponds formed by an ancient glacier inspired the creation of Central Park, and in the late 1800s helped make it the second most popular tourist destination after Niagara Falls” OR that it’s where Basquiat is buried?

Anyhow, that’s just one of dozens of events in NYC (how about a 4-hour brewery tour– by bicycle? Sounds dangerous, if you ask me) and around the world that will take place on April 9. Behind-the-scenes peeks and quirky tours are the order of the day: a penitentiary tour in Philadelphia; a brain collection tour in New Haven, Connecticut; and a visit to Pearl Fryar’s garden in Bishopville, South Carolina (Pearl was featured in the documentary “A Man Named Pearl.”). There’s plenty of stuff outside the US, too– even an exploration-themed event at McMurdo Station in Antarctica.

Ticket prices are low-ish for most events (I saw some as low as $2 and not many more than $20); the full listing is here.