The Giant Cactus — Saguaro National Park East. Join a ranger for a walk along a desert wash for a lesson in trees of the desert and a look at the only tree-like cactus in the U.S. Sturdy shoes and water are recommended. 11 a.m.- 1 p.m. Nov. 17. $20. 733-5153.

OUTDOOR ACTIVITIES

All events are free or included in admission or vehicle entrance fee unless otherwise noted. Bad weather may change or cancel activity. Children must be accompanied by an adult. No pets unless otherwise specified.

Geology "402" Walk With a Naturalist — Sabino Canyon recreation Area, 5700 N. Sabino Canyon Road. Naturalist led, moderate three mile hike that will explore faults, intrusions, boulder fields and other geological features of Sabino Canyon. 8:30 a.m.-noon. Nov. 14 and 21. Free. 749-8700. sabinonaturalists.org.

Who's Who — Saguaro National Park East, 3693 S. Old Spanish Trail. Walk through the cactus garden and get some hints to remember their names and faces. 3-3:30 p.m. Nov. 14. Free. 733-5153. nps.gov.

Ranger's Choice Patio Talk — Saguaro National Park East. A ranger will share stories about the park. Bring your questions or favorite topic. 10-10:30 a.m. Nov. 15, 21 and 22. Free. 733-5153. nps.gov.

The Saguaro Time Hike — Saguaro National Park East. Short hike to learn what it is like to live in a cactus forest, what people in this valley do today and what about the uncertain future. Ages 10 and up. 11 a.m.-1:15 p.m. Nov. 15 and 22. $20. 733-5153. nps.gov.

Come Gawk at the Garden — Saguaro National Park West, 2700 N. Kinney Road. Take a short walk through our Cactus Garden and discover some of the amazing plants and animals and how they adapt to the harsh Sonoran Desert. Wheelchair accessible. 3:15-4 p.m. Nov. 18; 11:15 a.m.- noon. Nov. 15 and 20. Free. 733-5158.

Presidio Block History Tour — Presidio San Agustín del Tucson Museum, 196 N. Court Ave. Includes a tour of the Presidio San Agustín del Tucson Museum and the Tucson Museum of Art and Historic Block, as well as a lunch at La Cocina. 11:30 a.m.-1:45 p.m. Nov. 15. $60. 837-8119. tucsonpresidio.com.

A Cactus or A ... sparagus? — Saguaro National Park East. Learn more about Agaves and Yuccas. Wheelchair accessible. 3-3:30 p.m. Nov. 15 and 22. Free. 733-5153. nps.gov.

Birding Canoa Ranch — Historic Canoa Ranch, 5375 S. I-19 Frontage Road, Green Valley. Join birding enthusiast Brian Nicholas to see a wide variety of sparrows, raptors, and the possibility of waterfowl on the pond. All ages. Register at pima.gov/canoaranch. 7:3-9:30 a.m. Nov. 16. $5. 724-5375. webcms.pima.gov.

Sonoran Desert Weedwackers — Tucson Mountain Park. Join the Sonoran Desert Weedwackers to eradicate buffelgrass and fountain grass in Tucson Mountain Park. Work requires hiking and digging buffelgrass on steep slopes. Meeting locations change frequently. Email eeducation@pima.gov for meeting location. Ages 18 and up. 8 a.m.- noon. Nov. 16. Free. 724-5375. webcms.pima.gov.

History Hike: Presidio Santa Cruz de Terrenate — Presidio Santa Cruz de Terrenate, In-Balance Ranch Road, Huachuca City. Join a docent from the Friends of the San Pedro River on a walking tour. Three-mile round trip walk over trails and uneven ground. The return walk is gradually uphill. No shade, bring water and suitable footwear. Donations accepted. 9-11 a.m. Nov. 16. Free. 459-2555. sanpedroriver.org.

San Pedro River Walk — San Pedro House, 9800 E. Highway 90, Sierra Vista. The Friends of the San Pedro River will conduct interpretive walks to find 82 species of mammals, dozens of reptiles and amphibians and nearly 350 species of birds. Bring water and suitable footwear. Donations accepted. 9-11 a.m. Saturdays. Free. 459-2555. sanpedroriver.org.

The Plants Tell All — Saguaro National Park West. Join a park naturalist to learn the secrets of what ties the plants and animals of the Sonoran Desert together. Closed-toed shoes, a hat, and water are required. 9:45-11:45 a.m. Nov. 16. Free. 733-5158. 

Historic Craft Demonstrations — Tumacácori National Historical Park, 1891 E. Frontage Road, Tumacacori. Traditional tortilla making on the mission grounds. 10 a.m.-4 p.m. Saturdays and Sundays. Free. 377-5060. nps.gov.

Tour of Historic Canoa Ranch — Historic Canoa Ranch. Walking tour of the Ranch. Register online. 10:30 a.m.-noon. Nov. 16 and 19. $5. 724-5375. webcms.pima.gov.

Living with Urban Wildlife — Kirk-Bear Canyon Public Library, 8959 E. Tanque Verde Road. Learn about local wildlife, and why they may be attracted to your yard or neighborhood. Presented by Pima County Natural Resources, Parks and Recreation naturalist Julie Strom. 11 a.m.-noon. Nov. 16. Free. 594-5275. pima.bibliocommons.com.

A Sticky Situation at Saguaro — Saguaro National Park East. View a photo gallery of cacti and learn the uses these plants have. Wheelchair accessible. 1-1:45 p.m. Nov. 16. Free. 733-5153. nps.gov.

Touring Arizona's Parks — Saguaro National Park East. Short tour of scenic and historical park areas. Wheelchair accessible. 3-3:30 p.m. Nov. 16. Free. 733-5153. nps.gov.

Bikes and Coffee at Roadrunner — Roadrunner Coffee Co., 9665 N. Thornydale Road. Ste. 110. All make and model motorcycle welcome. Food for purchase. 7-9 p.m. Nov. 17. Free. 579-7011.

Santa Cruz River Walk — Wheeler Taft Abbett Sr. Public Library, 7800 N. Schisler Drive. Take a guided stroll along the flowing Santa Cruz River on the Loop to discover the effects of water on desert habitats. All ages. Register at pima.gov. 10-11:30 a.m. Nov. 17. $5. 724-5375. webcms.pima.gov.

The Archaeology of Downtown Tucson Guided Walking Tour — Presidio San Agustín del Tucson Museum, 196 N. Court Ave. Join historian, Homer Thiel, for a walk to visit sites of former buildings. Learn about what has been recovered from the ground and what it tells us about Tucsonans of the past. 10 a.m.-noon. Nov. 17. $35. 837-8119. tucsonpresidio.com.

The Giant Cactus — Saguaro National Park East. Join a ranger for a walk along a desert wash for a lesson in trees of the desert and a look at the only tree-like cactus in the U.S. Sturdy shoes and water are recommended. 11 a.m.- 1 p.m. Nov. 17. $20. 733-5153. nps.gov.

Meet The Saguaro — Saguaro National Park East. Get to know the world's most famous cactus and learn its fascinating life story. Wheelchair accessible. 3-3:30 p.m. Nov. 17. Free. 733-5153. nps.gov.

Sonoran Lifestyles — Saguaro National Park East. Park naturalist leads a one mile walk to discover how plants and animals adapt to life in the desert. Wear comfortable walking shoes and bring water. Ages 10 and up. 10 a.m.-noon. Nov. 18 and 19. $15. 733-5153. nps.gov.

Desert Adaptations — Saguaro National Park East. Discover the fascinating world of desert plants and the many techniques they use to live here. Wheelchair accessible. 3-3:30 p.m. Nov. 18 and 19. Free. 733-5153. nps.gov.

Birding — Pima County Feliz Paseos Park, 1600 N. Camino de Oeste. Register at pima.gov/nrpr. 8-9:30 a.m. Nov. 19. $5. 724-5375. webcms.pima.gov.

Naturalist Guided Geology "401" Walk — Sabino Canyon Recreation Area. Learn the geological history of our planet, and of Sabino Canyon in an easy 1.4 mile walk led by Sabino Canyon Volunteer Naturalists. 8:30-11 a.m. Nov. 19. Free. 749-8700. sabinonaturalists.org.

Life Cycle of the Saguaro: Seeds to Giant — Saguaro National Park West. Hear some astonishing reasons about why so few Saguaro seeds make it to fruition. 11:15 a.m.- noon. Nov. 19. Free. 733-5158.

A Taste of the Desert — Saguaro National Park East. Learn what plants can be used for food, clothing, medicine and shelter. Wheelchair accessible. 1-1:30 p.m. Nov. 19. Free. 733-5153. nps.gov.

Synergy in the Desert: The Sonoran Habitat — Saguaro National Park West. Discussion of how the parts of the Sonoran Desert work together to create a rich living desert that is unique in the world. 3:15-4 p.m. Nov. 19. Free. 733-5158.

Showers of Saguaros — Saguaro National Park East. Presentation in the park theater about the magic of rainfall in the desert. Wheelchair accessible. 9:30-10 a.m. Nov. 20. Free. 733-5153. nps.gov.

Arizona History Tour — University of Arizona, 811 N. Euclid Ave. Experience the University of Arizona through the eyes of an alumnus and learn our rich history and traditions that began over 130 years ago. Reservations are required. Guests under 18 years of age must be accompanied by an adult. 10-11:30 a.m. Nov. 20. Free. 621-5130. visitorcenter.arizona.edu.

What's New at Saguaro National Park? — Saguaro National Park East. Join park staff in the visitor center theater to take a look at the Rincon Mountains and the new plant species recently discovered up there. Wheelchair accessible. 11-11:30 a.m. Nov. 20. Free. 733-5153. nps.gov.

Turquoise Trail Guided Walking Tour — Presidio San Agustín del Tucson Museum, 196 N. Court Ave. A docents will lead a walk along the 2.5-mile Turquoise Trail through downtown to see historic buildings and hear stories that make Tucson's history special. Pre-registration suggested. 10 a.m.-12:30 p.m. Nov. 21. $20. 837-8119. tucsonpresidio.com.

Star Party — Saguaro National Park East. Join park naturalists for an introduction to astronomy and a look at the desert night sky. Telescopes and binoculars will be available. Call for reservations. Wheelchair accessible. 7-9 p.m. Nov. 21. Free. 733-5153. nps.gov.

Sonoran Secrets to Desert Survival — Saguaro National Park West. Stroll the Cactus Garden and identify the most common hazards hidden in the desert, uncover survival strategies of native plants and animals, and acquire practical tips to ensure your safety. Wheelchair accessible. 10:15-11:15 a.m. Nov. 22. Free. 733-5158.

Investigation of the 1000 Year Old Rock Art — Saguaro National Park West. Become a rock art detective and investigate the who, when, and how mysteries of the 1000 year old Hohokam Petroglyphs. 11:15 a.m.-noon. Nov. 22. Free. 733-5158.