Complex sentence: Modern visitors can also see a 25-metre tall pink granite obelisk: this one of a matching pair until 1835, when the other one was taken to Paris where it now stands in the centre of the Place de la Concorde.
Split into simpler sentences: Modern visitors can also see a 25 metre (82 ft) tall pink granite obelisk: it is one of a matching pair. The other was taken to Paris in 1835 where it now stands in the centre of the Place de la Concorde.