Did you know that Lake Roland was Baltimore City’s first water supply?

Construction began on the “indestructible” dam and the lake serviced the city until 1915. Water quality issues — a Baltimore County newspaper referred to the lake as a “receptacle of filth” — and the creation of the nearby Loch Raven Reservoir eventually relegated the lake to a 500-acre park, according to the Maryland Center for History and Culture.

In the 21st century, the lake and the surrounding park is best known for its picturesque hikes, wetlands and nature scenes.

This weekend you can join Baltimore County’s recreation and parks department for the Dam Jam Festival along with many more countywide events.

Here’s a look at some things to do in Baltimore County for the week ending Nov. 19.

‘Erased: A Daughter’s Search’

Wednesday, 7-8:30 p.m.

What happened to Jill Yesko’s mother? The filmmaker and journalist explores her mother’s yearlong stay at a New York psychiatric hospital when Yesko was a child in her new documentary: “Erased: A Daughter’s Search.” The film is screening at 7 p.m. at Towson Unitarian Universalist Church in Timonium. There will also be a Dec. 3 showing at the Johns Hopkins Bloomberg School of Public Health.

Play Clue IRL

Friday, 7-9:30 p.m.

Who did it? And why? Act out your inner Professor Plum, Colonel Mustard or Miss Scarlett during the Murder Mystery Dinner Theater’s coming show at 705 North Hammonds Ferry Road in Linthicum Heights. Tickets are $69 plus fees. Hosted at the Olive Grove Restaurant, you can purchase tickets here.

Holly Fair on Main Street

Saturday, 9 a.m.-3 p.m.

Want to support local artists and get your holiday shopping in order? Join the Holly Fair on Main Street at 246 Main St. in Reisterstown. You can peruse hand-crafted, artisanal items from among more than 40 different vendors.

Jam at the dam

Saturday, 10 a.m.-2 p.m.

The Baltimore County Recreation and Parks Department is hosting the Lake Roland Dam Jam on Saturday at 1000 Lakeside Drive in Baltimore. The event features a day of live music, vendors, nature activities and more. Participants are encouraged to bring their Nature Quest passports to fill out and turn in for prizes.

Mortified at Manor Mill

Saturday, 7-9 p.m.

Too embarrassed to even think about your middle and high school diary entries? Luckily, there are more daring, slightly insane adults ready to pour out their hearts from their teenage years during “Mortified Baltimore,” a live show featuring the benign, unbelievable and remarkable artifacts of journals, love letters and locker notes past. Tickets are $27.50 for the show, which will be at Manor Mill, 2029 Monkton Road.

Fairy Scary Ball

Saturday, 7 p.m.-midnight

Calling all dreamers and doers, poets and musicians, those born in the wrong generation (or perhaps century) — come celebrate the magic of the Baltimore Faerie Fair this weekend with the festival’s main event, the Fairy Scary Ball at 903 Dulaney Valley Road in Towson. The cost of the ball is $175, available online through Friday.

Feel the beat

Sunday, 1:30-2:30 p.m.

The Baltimore County Arts Guild is hosting an African Drumming Class with instructor Baba Djuann, who will teach the fundamentals of African drumming. Whether it’s learning the urban sound of West Africa’s markets or understanding the rhythm behind East African ceremonies, tickets can be purchased through the Catonsville Clubhouse. The class will be offered at 10 St. Timothys Lane. A single ticket is $20 and a double ticket is $35.