Crowds gathered to see the outcome of two years and £4.4 million worth of work at the Rotunda, which has been heralded as the "jewel in the crown of Britain's geological heritage". After being officially reopened by former Coronation Street star Susie Blake, more than 600 visitors passed through the doors on Saturday.

The museum had to be kept open for an extra hour due to the overwhelming response to a free entry offer in the Scarborough Evening News.

Shirley Collier, chief executive of Scarborough Museums Trust, said: "We have had brilliant feedback from the visitors. They think it is wonderful and I am so pleased they are impressed with the finished product. From what I can gather the dinosaur coast gallery has been very popular. I hope people will be inspired to go out and find their own fossils which they can bring in and inspect on their next visit to the Rotunda."

A whole weekend of events was held for the public to celebrate the opening. Art workshops were arranged for children, with face painting and dinosaur mask making, along with a magic show.

One of the first through the doors was six-year-old Ben Standaloft, from Caledonia Street. He said: "I loved the dinosaur and I liked seeing their footprints. I really like dinosaurs. The skeleton was good too, it was gigantic. I can't wait to come back again."

The three galleries of the museum have been designed to capture the interests of all ages.

The extension to the front offers a display of colourful minerals and fossils lying beneath the first floor of the original museum, which opens up like a jewellery box.

The Shell Geology Now gallery using interactive multimedia to present geological information, is in one wing, while on the opposite side there is the Dinosaur Coast Gallery, which looks at the coast from Flamborough to Redcar.

Peter Waller, 78, and his wife Jean, 76, had been eagerly awaiting the reopening for some time. Mrs Waller said: "I think it is really really good, and it was well worth the wait. We especially liked the top gallery in the original part of the museum. We could have spent hours and hours just taking it all in, it was all so interesting.

"It was nice to see the children taking such an interest too. The little ones were all so excited and you could see they loved the interaction."

Various performers entertained the crowds outside during Saturday's sunshine including dancing from Scarborough Hip Hop School and the Hatton School of Performing Arts. There was also music from The Pieces as well as Whitby Community Choir.

On Sunday the Scarborough Symphony Orchestra and Yorkshire Coast Morris Dancers provided the entertainment along with music from Dave Tomlinson, Alistair James, and opera singer Victoria Wright.