There's a whole lot of wild next door to Irvine's burgeoning malls and businesses. Limestone Canyon and Whiting Ranch Wilderness Park has 4,300 acres of wilderness that’s been saved from development. Embark on a 5.75-mile moderately challenging mountain bike loop through two of the park's oak-shaded canyons. Gaining traction on patches of sand is part of the fat-tire fun while coursing up Borrego Canyon Trail for the first 1.5-miles. Mule deer can often be seen sourcing a meal from the oak groves flanking the path. A few fun descents keep things interesting, but the ride is mostly easy-going en route to the Mustard Trail junction, where it'll be time to get your game face on: this part involves tackling 400 feet of elevation gain in just under a mile. The good news: you’ll be privy to grand views of the surrounding foothills and saw-toothed sandstone faces. After topping out, set your sights east to a magnificent view of Santiago Peak. Then you're free to fly! Descend a sage-covered ridge to Serrano Canyon, where you'll zip through more oak woodlands on a wide, well-maintained trail that leads to the bottom. Tie the loop together via a short ride on a paved bike lane back to the trailhead. Two canyons in the can!

Take I-5 to the Bake Pkwy. exit in Irvine (just south of the merger with I-405). Drive east for 5.3 miles to Portola Pkwy. Turn left and drive one block to Market Pl. Turn right and make an immediate left into the parking area for Whiting Ranch Wilderness Park. There is a $3 fee to park in this lot. Grab a trail map and bike 1.5 miles up Borrego Canyon Trail. Turn right on Mustard Trail and proceed 0.8-mile to a four-way junction. Head straight down Whiting Rd., and continue downhill on Serrano Cow Trail and Serrano Canyon Trail to reach the second trailhead. Pass through a metal gate and turn right toward Portola Pkwy. Turn right and take the bike lane 0.9-mile back to the start. All junctions are marked. Bike traffic on Borrego Canyon Trail is one way, so do not attempt the loop in reverse. No dogs.