San Francisco has always been a walking city, but this October the city is giving that habit a name: Walktober.

The first citywide celebration runs throughout the month with organized walks, urban hikes and neighborhood explorations designed to get residents out of their usual routines and onto streets and trails they may have never noticed.

At the center of the movement is the Crosstown Trail, the 17-mile route connecting Candlestick Point with Lands End through parks, residential neighborhoods, stairways, commercial corridors and some surprisingly wild corners of San Francisco.

You do not have to walk all 17 miles to understand the appeal.

The trail can be tackled in sections, making it just as useful for a relaxed afternoon outing as for walkers and runners looking for an all-day challenge.

The fun is in discovering how quickly San Francisco can change when you experience it at walking speed.

A route can move from a busy neighborhood street to eucalyptus trees, tiled stairways, community gardens and broad ocean views in surprisingly little time.

The Crosstown concept has also expanded beyond the original route, giving walkers more ways to stitch together neighborhoods and open spaces across the city.

Walktober builds on that idea with dozens of outings ranging from short social walks to much longer urban treks.

Some focus on nature, others on history, transit, architecture or neighborhood culture, which means the month is less about exercise alone than about seeing familiar places differently.

For residents who want to create their own San Francisco walks, there is no shortage of starting points.

Lands End remains an obvious favorite for dramatic coastal scenery and Golden Gate views, while Golden Gate Park offers flatter stretches and plenty of opportunities to wander without worrying much about a destination.

For hills and sweeping city views, routes around Mount Davidson or the central peaks deliver a very different San Francisco experience.

And for anyone who thinks hiking requires leaving town, the city's stairways, greenways and dirt paths make a convincing argument otherwise.

The best San Francisco hiking trails often begin just a few blocks from a Muni stop.

That accessibility is part of what makes urban walking here so appealing.

You need comfortable shoes, a layer for changing weather and perhaps a little patience with the hills, but very little else.

Walking also reveals details that disappear from a car window: a tiny garden tucked beside a staircase, an old neighborhood sign, a view between houses or a business worth returning to later.

For October, the challenge is simple.

Pick a neighborhood you do not know well, find a route that crosses it and give yourself permission to take the long way.

In a city only about seven miles across, there is still an impressive amount of San Francisco left to discover one step at a time.