The beautiful city has an ugly face.

Thankfully, I have experienced only kindness from the people I've met in Rio. However, a frightening incident that some British guys recounted to me has reminded of this place's reputation as one of the world's most dangerous and corrupt cities, and that every experience it offers errs on the extreme.

On leaving a club last Thursday morning they got into a taxi to go to their hotel; they immediately knew something was wrong. The windows wouldn't wind up, the driver wouldn't use the meter, and within seconds police were around the car and guns were being pushed to their heads.

They were taken to an ATM and 5000 Reis, about 1500 GBP, was demanded from them. They negotiated down to 2000 R, paid and, this being Rio, the police dropped the boys back at their hotel afterwards.

In a place where lawlessness is common and authority figures cannot be trusted, the incident was apparently as scary as it sounds.

Rio is a place of such extremes and contrasts, a hyper-city on speed: the most beautiful and ugly; the richest and poorest; the most privileged and foresaken; and the most compassionate towards human life, and the cruelest. Moderation is not something it has time for.

Ultimately this city seems a distillation of humanity's greatest achievements and strengths, as well as its worst failings and weaknesses.