It's theoretically possible to visit the Canyon's highlights in a single day via a tour from Arequipa. However, "day" might be stretching it slightly as you have to leave at around 3 am and arrive deep into the night, hours at both ends seemingly used only by airport departures and arrivals and nocturnal revelers. A more sensible approach, which I followed, is to take a two-day tour which picks you up around 8 am one morning and drops you off the next evening at 5 pm. The price isn't much higher (although it rarely includes any meals besides a rudimentary breakfast) and the pace is slightly more relaxed. If you're particularly physically fit and don't have problems at high altitudes, several friends of mine have spoken highly of a 2 or 3 day hike in the canyon - but while I'm an enthusiastic hiker the altitude (which can reach 4,500 meters in some places) was a bit much for me so I'll have to pass this along as hearsay. You can also go by public transportation, which is safe but only a little cheaper than if you arrange the trip through a tour agency and means you have to work out travel between the points of interest in the canyon which is difficult without your own vehicle since the only local taxis I saw were of the tricycle variety.

Regardless of how long you go for, your itinerary is likely to include some mixture of photo opportunities, hiking, watching wildlife, and seeking to appreciate local culture by visiting the valley's colonial churches and perhaps watching local dancers (who are often to be found outside said churches). If none of these appeals to you, I doubt the canyon would - but if any of the first three do it's well worth the effort of going. Before doing so, however, make absolutely sure you have spent time to get acclimated to the altitude in Arequipa and pack alcohol, cotton wool, and some altitude sickness pills. Any reputable tour agency will either have these or stop en route to pick them up, but I can't stress strongly enough how important they are since fully half of my tour group succumbed to altitude sickness in some form or other. The canyon is very cold at night and scorching in the day, so plan accordingly with a jacket, a good hat, and lotion.

In my opinion, the Canyon's two most emblematic animals are vicuñas (shy wild relatives of llamas and alpacas) and condors. Technically speaking, you won't see the vicuñas in the canyon but rather on the way. While shy they often stop photogenically by the road and their enormous black eyes and plaintive expressions are quite different from their more circumspect and aggressive domestic cousins. Their wool is the finest in the world and they were nearly hunted to extinction because of it - today they're recovering in numbers and are occasionally rounded up and sheared. Condors, which you'll likely see in the Canyon itself at the so-called "Cruz del Condor" (Cross of the Condor) are among the world's largest flying birds and have been used since time immemorial in South America as an important symbol of power. Other animals you may come across include vizcachas (long-whiskered rabbit-like rodents), flamingos (on the way to the canyon) and Andean ducks.

The extent of photo opportunities and hiking will depend on your trip and guide. At the least you'll have the chance to clamber along the canyon's side near the Cruz del Condor for an hour or so (as I did), while on a longer hiking specific trip you can go deep in the heart of the canyon itself. Despite the relatively dry climate in the canyon and around Arequipa generally, it has be farmed for centures by the Collagua and Cabana peoples. The brightly colored hats worn by their women serve to distinguish them from one another as the Collaguas wear one type and the Cabanas another - before the Spanish conquest this distinction was achieved by cranial deformation.

The churches that dominate the main square of every town in the valley are the most potent reminder of the Spanish presence. So too are the local dances, which you may well be treated to in front of these churches which were in many cases intended as subtle criticisms of Spanish rule. The presence of a single dancer who breaks free from the group and carries a pot to tourists in search of donations is a more recent innovation, as are women who have tamed hawks and eagles and will let you pose with them for a fee. Many of the towns in the canyon, especially Chivay, the capital (which is actually just outside it) have nightly performances of these dances where you make payment a bit more directly and beforehand.

For many years, Colca's claim to fame was as the world's deepest canyon, twice as deep as the Grand Canyon, although scientists have since found that the nearby (but difficult to access) Cotohuasi Canyon is actually slightly deeper. Stripped of this superlative, Colca is a pleasant enough place to visit, and an agreeable place for a change of pace from Arequipa. While the presence of wildlife that I had not previously seen was a highlight for me, I was not as impressed by the scenery as I was by the Sacred Valley near Cuzco and I would personally hesitate to label Colca one of Peru's natural highlights. It's certainly worth seeing if you're near Arequipa, but I don't think it's worth going out of your way (or risking altitude sickness if you're susceptible to it) for.

It's the deepest canyon in the world and has a placed viewpoint (Cruz del Condor) at the deepest section, where you can see huge condors majestically soaring on the early morning thermals.

But I must admit that the experience left me rather cold. Initially, this was entirely due to the freezing conditions at 7am at 4,000m. But then, as the day warmed up, the action didn't.

The Canyon
It's difficult to make sense of the depth of the canyon. It's certainly very deep (3,191m), but that isn't so exciting. The impact only hits when you realise that you could lose Ben Nevis (or Mount Washington for those in the US) in there and still have room.

Actually, the deepest canyon in the whole world is Cotahuasi Canyon, metaphorically just round the corner from Colca. But the difference is only 163m, which isn't much over 3km vertically.

The Condors
So the condors. The big attraction. And big is the word. With wingspans of over 3m (about the size of a Mini), you can see them coming from a distance, which is just as well, as there aren't that many of them.

I'm there from 7am until 10am, and we see only seven birds out of the population of about 40. And we see all but two of those between 9 and 9:30am. Apparently, at 12kg, condors are the heaviest bird that can fly, and if they eat a bit too much, they can't take off. I can only assume they were out for a feast last night.

But the lesson is there. The birds are likely to be around from 9am. Most tourists are there from about 8am to get a good spot. Don't do what I did and get there at 7am. It's just cold.

The Logistics
Many agencies in Arequipa will offer you a 1-day tour. Don't take this, as you can't avoid the 10 hours of travelling.

Go for 2 days. You can go with the agencies for approximately US$20, which is all very easy.

I tried it the hard (stupid?) way and did it myself. Day 1, afternoon bus to Chivay. Day 2, get 5am bus from Chivay to the Cruz del Condor, see the Condors, then bus back to Arequipa. So was it worth it?

I did it for about US$14, which is a reasonable saving. There's an extra US$7 for the park ticket, but that's not in the agency prices either. And I was about half a day quicker (on Day 1), but then I didn't stop at so many places. But I avoided the tourist-trap lunch and the hellish folklore show.

Summary
I was disappointed by the Colca Canyon, as it was a lot of travelling for not so much. If you are tight on time, I would suggest that this is one attraction that could be missed.

If your tour group does not include a trip here, take a taxi (which may or may not be a cart on the back of a bicycle!). Take money to get in here, but not much more, as there is no place to lock your belongings there.

There are three different pools of different sizes and temperatures, but all are more than hot enough to warm you up and be completely relaxing.

You can also order alcoholic and non-alcoholic drinks to sip in the pools! For a special treat, go there in time to watch the sun set over the hills. You really are in the middle of nowhere at this point, so when it gets dark, the stars come out so brightly!