CU Symphony Orchestra: Fantastic Symphony! — This program includes the audacious and thrilling “Symphonie Fantastique” by Hector Berlioz. Soprano Sabina Balsamo, winner of the graduate division of the College of Music’s Honors Competition in early 2019, will perform “Four Last Songs” by Richard Strauss. The program will open with Berlioz’s tuneful and exciting “Roman Carnival Overture”; 7:30 p.m., Macky Auditorium, 1595 Pleasant St., Boulder; free.
Nature Detectives in the Field: Beetles Recycle! — People aren’t the only species that recycle — some beetles perform all sorts of favors for nature by recycling or reusing things like poop and dead animals. Discover the antics of these hard-working little insects and find out how being gross can lead to something great. For ages 5-10 with accompanying adult. Register at bouldercountyopenspace.org/register; 10 a.m., Sept. 24, Location provided to registered participants, near Boulder, Boulder; free; 303-678-6214.
Climbing Volcanoes in Mexico — The Mexican volcanoes are among the highest peaks in North America checking in at over 18,000 feet. A great accomplishment for lovers of 14ers, the volcanoes are also a favorite training ground for climbers who want to explore higher elevation objectives all over the world; 5:30 p.m., Sept. 24, Neptune Mountaineering, 633 S. Broadway, Boulder; free; 303-499-8866.
The Boulder Hiker Chicks: Creating Community One Hike at a Time — Don’t miss this awesome Speaker Series event featuring the founders of “The Boulder Hiker Chicks.” Alli and Kari will tell the story of how the BHC came to be, why it’s resonated so much with local women, what to expect on a typical BHC hike, why they keep doing it and what the future holds for the group. Q&A to follow; 6 p.m., Sept. 24, Go Far Shop, 2005 Pearl St., Boulder; free; 720-428-8965.
Essential Oils 101 — Always wanted to learn about and use essential oils but didn’t know where to begin? Here’s a fun, hands-on class to learn how to use them in daily life to support emotional, physical and spiritual well-being. We’ll cover how to safely use them for yourself, family and pets. Take home a custom blend; 6:30 p.m., Sept. 24, Platt Middle School, 6096 Baseline Road, Boulder; $32; 720-561-5968.
Opperman Photographics Evening Presentation — Stop by FRBC Boulder for an informative and inspirational evening with award-winning photographer Cheryl Opperman as she shares her images from around the world, provides tips for traveling with camera gear, and highlights her upcoming photo workshops and tours; 6:30 p.m., Sept. 24, Front Range Birding Company, 5360 Arapahoe Ave., Ste. E, Boulder; free; 303-979-2475.
Sister Helen Prejean: “River of Fire” — Sister Helen Prejean will speak about and sign her new book, “River of Fire: My Spiritual Journey”; 7:30 p.m., Sept. 24, Boulder Book Store, 1107 Pearl St., Boulder; $5; 303-447-2074.
Donation-Based Yoga — noon, Wednesday, Sept. 25, Frog Pose Yoga, 2900 Valmont F1, Boulder; free; 970-408-1902.