Warmer temperatures during the summer months drive native elk herds toward higher elevations. A small group of visitors observe this bull elk near the Alpine Visitor Center trailhead. Elevation: 11,796 feet.

Photo by Dan Coburn

Park volunteer Dennis Lee smiles for a portrait in front of the ranger station at Bear Lake trailhead. Volunteers play a significant role in the maintenance and operation of the park. Annually, the park has approximately 2,000 volunteers working in more than 100 different job descriptions, giving it the largest volunteer program in the National Park Service.

Photo by Dan Coburn

On a typical summer day, strong thunderstorms pass through the park in the afternoon. This visitor finds a moment of solitude beneath a turbulent sky, standing atop a rock formation near the Alpine Visitor Center. Lightning strikes are a major safety concern for visitors and staff in these areas above the tree line.

Photo by Dan Coburn

Hundreds of aspen trees in a grove near the Alberta Falls Trail have been scarred with graffiti by visitors through the years.

Photo by Dan Coburn

Tree roots grow from a rock formation near Dream Lake in Rocky Mountain National Park. The park’s ecosystems are sometimes fragile and sensitive to human presence. However, several species of wildlife and vegetation have adapted to survive some of the harshest environmental and climate conditions.

Photo by Dan Coburn

Reaching an elevation of 12,183 feet, Trail Ridge Road is the highest continuous paved road in the United States. Efforts to repave and repair parts of the road have slowed heavy traffic during months of peak visitation to Rocky Mountain National Park.

Photo by Dan Coburn

A toddler enjoys the view from an overlook at the Alpine Visitors Center. Visual records of early artists helped to stimulate the establishment of many of our national parks. These artists translate the national park’s purpose, as a place of pleasure and preservation, into images which bring others enjoyment and a deeper understanding of the parks many Americans may never visit.

Photo by Dan Coburn

A large group of park visitors makes their way toward the Glacier Gorge overlook. Rocky Mountain National Park receives more than 3.5 million visitors annually. Heavy foot traffic is a concern in fragile areas of the park.

Photo by Dan Coburn

Park ranger/interpreter Sue Langdon leads a group of visitors on an informational hike through the high country. Approximately one-third of this national park is above the limit where trees may grow in northern Colorado. Repeated footsteps often destroy tundra plants, leaving exposed soil to blow away, and recovery may take hundreds of years.

Photo by Dan Coburn

Gavin Browning enjoys exciting opportunities to interact with wildlife in the park. Many families return year after year, generation after generation, to see the natural wonders of the park.

Photo by Dan Coburn

The mountain pine beetle has caused major damage to pine forests throughout the Rockies. The increased beetle population can be attributed in part to the reduction in the severity of winters. Some fear that global warming will cause the problem to intensify.

Photo by Dan Coburn

Summer rain and sunlight create a spectacular display and illuminate mountain peaks over Morraine Park.

Photo by Dan Coburn

The trailhead at Milner Pass provides hikers with several options for treks along the continental divide.

Photo by Dan Coburn

A pair of hikers wade accross the Big Thompson River, which meanders through Moraine Park in the heart of Rocky Mountain National Park. Headwaters of the Big Thompson originate on the eastern slope of Longs Peak.

Photo by Dan Coburn

Clint Murrow of Laredo, Colo., sits for a portrait. Rocky Mountain National Park attracts a diverse cross-section of people from all different races, religions, nationalities and cultural backgrounds.

Photo by Dan Coburn

Park visitors enjoy the afternoon sunlight on a boulder near Albert Falls.

Photo by Dan Coburn

An elderly couple from Nebraska, both 80 years old, enjoy a hike to Dream Lake. They have been visiting Rocky Mountain National Park every year for the past two decades. The trek to Dream Lake includes more than two miles (round-trip) of steep and winding trails.

Photo by Dan Coburn

This young hiker from Georgia breaks from his hike for a moment of reflection.

Photo by Dan Coburn

From the banks of Dream Lake, the view is almost surreal.

Photo by Dan Coburn

In the foreground, the ruins of a wall used by American Indians to route game through their hunting grounds remain, and a Trail Ridge Road winds accross an eastern slope of the Rockies in the background.

Photo by Dan Coburn

Afternoon sun peeks through low clouds over Flat Top Mountain.

Photo by Dan Coburn

A lone visitor gives a sense of scale to the massive rock formations near Rock Cut Overlook in the alpine tundra of Rocky Mountain National Park.

Photo by Dan Coburn