Short answers, pulled from the story.
Roman Britain began with the Claudian invasion in AD 43 and ended around AD 410, when the remaining Roman administrative structures collapsed following decades of barbarian pressure and imperial withdrawal. The occupation lasted approximately 367 years.
Julius Caesar invaded Britain in 55 and 54 BC as part of his conquest of Gaul, believing the Britons were aiding the Gallic resistance. The first expedition was largely a reconnaissance, and Caesar conquered no territory and left no troops behind, but he established Roman clients and brought Britain into Rome's sphere of influence.
Boudica was the widow of Prasutagus, king of the Iceni tribe. When Prasutagus died, Rome ignored his will and seized the tribe's lands in full; Roman forces flogged Boudica and assaulted her daughters. She led the Iceni and the Trinovantes in an uprising that destroyed Camulodunum (Colchester), Londinium, and Verulamium (St Albans), killing between seventy and eighty thousand people before being defeated at the Battle of Watling Street.
Both walls were built to defend Roman Britain from the Caledonians to the north. Hadrian directed the construction of Hadrian's Wall around AD 120, built largely of stone close to the Stanegate frontier. The Antonine Wall, built largely of turf around 142 under Antoninus Pius, pushed the frontier north to the Forth-Clyde isthmus but was abandoned by 163 or 164, after which Hadrian's Wall became the permanent northern boundary.
Roman Britain had an estimated population of between 2.8 million and 3 million people at the end of the second century, rising to an estimated 3.6 million by the end of the fourth century. Of that later figure, approximately 125,000 were Roman army personnel and their families. The capital, Londinium, held an estimated 60,000 people.
Rome left behind an extensive road network still partially in use today, the foundations of major cities including London, Manchester, and York, roughly 800 Latin words absorbed into the Brittonic language, and evidence of new species introduced to the island including the edible snail Helix pomatia and the box tree. The demographic diversity of Roman Britain was also significant: a 2012 study found that around 45 percent of investigated Roman-period sites contained at least one individual of North African origin.