The O event at the City of London looks awesome. I always thought that would be a great place to orienteer. They weren't able to control traffic, I assume?
The London race was awesome. Saturday morning is very quiet in the city and there isn't _that_ much traffic - but you did have to dodge the odd vehicle. More of a problem was all the cranes that blocked all the roads - there are more than 50 building sites on the map and it seemed like all of them had a temporary crane almost blocking one of the adjacent roads!