The North Tower of Founders, the first thing people see coming into Royal Holloway
Egham itself does not really have a lot to offer; its High Street is okay for those who live there but not particularly interesting for any outsiders. The thing that Egham is famous for is that the Magna Carta was signed here in 1215. The town only has a population of about 7000 but it is the location of Royal Holloway, which is part of the University of London
and adds about 6500 students to the town during term time. Royal Holloway also offers what is probably Egham's main attraction, namely the Founders building. People like me who live in the area sometimes take their visitors to Royal Holloway to show them the Founders building. I also did my undergraduate degree there and the entire campus still feels like home to me in some ways. Although I never lived in Founders myself, its architechture still impresses me when I go back.
One funny thing is that the person who had Founders built wanted it to look like the typical kind of castle but when he arrived to take a look he said "more chimneys!" So Founders really has a LOT of chimneys, most of which are fake and do nothing. It's a nice building to go round in, even though it is a little run down in some places. Just make sure you don't get lost :)