Although there is some evidence of earlier inhabitation in the region of Utrecht, dating back to the Stone Age (app. 2200 BCE) and settling in the Bronze Age (app. 1800–800 BCE), the founding date of the city is usually related to the construction of a Roman fortification (castellum), probably built in around 50 CE. A series of such fortresses was built after the Roman emperor Claudius decided the empire should not expand north. To consolidate the border the limes Germanicus defense line was constructed  along the main branch of the river Rhine, which at that time flowed through a more northern bed compared to today (what is now the Kromme Rijn). These fortresses were designed to house a cohort of about 500 Roman soldiers. Near the fort settlements would grow housing artisans, traders and soldiers' wives and children.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What area area was first settled in the Stone Age?
Ah, so.. unanswerable

Bermuda's economy is based on offshore insurance and reinsurance, and tourism, the two largest economic sectors. Bermuda had one of the world's highest GDP per capita for most of the 20th century and several years beyond. Recently, its economic status has been affected by the global recession. It has a subtropical climate. Bermuda is the northernmost point of the Bermuda Triangle, a region of sea in which, according to legend, a number of aircraft and surface vessels have disappeared under supposedly unexplained or mysterious circumstances. The island is in the hurricane belt and prone to severe weather. However, it is somewhat protected from the full force of a hurricane by the coral reef that surrounds the island.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What protects the island from storms?
Ah, so.. coral reef that surrounds the island

The study of the Quran and the Hadith thrived in such a scholarly atmosphere. Philosophy, Fiqh and theology (kalaam) were further developed, most noticeably by Avicenna and his opponents. Al-Razi and Al-Farabi had provided methodology and knowledge in medicine and philosophy. Avicenna had access to the great libraries of Balkh, Khwarezm, Gorgan, Rey, Isfahan and Hamadan. Various texts (such as the 'Ahd with Bahmanyar) show that he debated philosophical points with the greatest scholars of the time. Aruzi Samarqandi describes how before Avicenna left Khwarezm he had met Al-Biruni (a famous scientist and astronomer), Abu Nasr Iraqi (a renowned mathematician), Abu Sahl Masihi (a respected philosopher) and Abu al-Khayr Khammar (a great physician).
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What is the name of one library that Avicenna didn't have access to?
Ah, so..
unanswerable