History's a Mystery Once More. History's a Mystery series, #4

In this fourth book, Olivia and her friends Grace, Will and Jack are in Year 6 at Coolongawong Public School in outback New South Wales and continue to enjoy the wonders of time travel in their magic classroom. They have already spent a year with their awesome teacher, Mr Mac. Early on they discovered that they could have magical adventures back in time by tripping on a creaky floorboard and saying the magic words, discovering history as it was being made in exciting, and sometimes dangerous, adventures.
They visit many new places together, including Tutankhamen' tomb and Cleopatra in Ancient Egypt, an underground city in Turkey, Louisbourg and Paris during the storming of the Bastille. They find themselves performing in Barnum and Bailey's circus and discover what school was like back in the nineteenth century. They travel to Japan, Africa, Panama and many other places as they witness history in the making.
They are present in Darwin during Cyclone Tracy and meet Harry Houdini, Mozart, Boudicca and Breaker Morant. Matt, Nicky, Ben and Kris also return for an adventure back to New York during the terrorist attack on the twin towers.