A scientist invents a time machine and uses it to travel hundreds of thousands of years into the future, where he discovers the childlike Eloi and the hideous underground Morlocks.

"Mason and Ty were once the very best of friends, like two nerdy sides of the same coin--until seventh grade, when Ava Petrakis came along. Now Mason can trace everything bad in his life to that terrible fight they had over the new girl. The one thing he'd give anything for is a do-over ... As a science kid, Mason knows do-overs are impossible, so he can't believe it when he wakes up from a freak accident and finds himself magically transported back...

Magic tree house series, #4. The magic tree house whisks Jack and Annie back to the days of deserted islands, secret maps, hidden gold, and nasty pirates.

The magic treehouse takes Jack and Annie to a moon base in the future where they continue to search for the fourth thing they need to free their friend Morgan from the magician's spell.

When Corey learns that he has the ability to save lives while time traveling, he is determined to go back in time to save his grandmother who died on September 11, 2001.

Ever since Corey Fletcher found out that he's the world's first "throwback," with the power to not only visit history, but change it, he's been spending as much time in the past as possible. Corey loves using his skills to fix problems and help his friends and family. But as Corey becomes more and more addicted to rewriting history, he learns that time travel might change him in ways he may never be able to reverse. Aware now that he can't keep going...

Jack and Annie ride a tree house to the Amazon rain forest where they encounter flesh-eating piranhas, hungry crocodiles, and wild jaguars.

The mysterious box that Ranger the golden retriever found in the garden transports him back to first century Rome, where he must rescue Marcus, a young servant boy, and Quintus, a volunteer gladiator, from the brutal world of the Colosseum.

Geronimo Stilton travels back in time to the ice age, ancient Greece, and Renaissance Italy, where he experiences wild historical adventures.

"After eleven-year-old David Bravo wishes for a do-over of a disastrous day of middle school, he and a shapeshifting spirit guide try to right a wrong in his past"--