And "at the the Colosseum" could be also be used in certain situations.
That is, when in the sense of "being in the general vicinity":How Not To Pose For Photos At Pisa Tower. Funniest Photos You Will Ever See...
(ou...como pagar um mico...quando for tirar fotos na Torre de Pisa - na "área perto - sendo qualquer área perto" da torre citada..)And, there is the other situation in which the usage of AT is acceptable, to mean that you are at a place for a purpose (a meeting etc), in our case you are visiting
(e.g. In a tour) and also when the said place is a well-known landmark
:So here I am, at the Louvre with no cell phone service and no wifi. We're making our way through the Ancient Egypt section of the museum.
These photos were my catalyst. I have a love/hate relationship with them. The next time I am at the Louvre, the photo will be MUCH different!
"I am in China. I am at the Great Wall.
This was the time when all scholars went with the belief of Aristotle, that "the rate of fall was proportional to the weight of the body". This, Galileo showed, was an erroneous conclusion, by his simple demonstration at Pisa Tower, in 1587, when he was 23.
(with this one the Galileo´s purpose was to make an experiment, and again, the Pisa Tower is a landmark in that city.
To every, or almost every rule there´s a caveat.