Question: The 1469 marriage of Isabella I of Castile and Ferdinand II of Aragon and the 1479 death of John II of Aragon led to the creation of modern-day Spain. In 1492, Granada was captured from the Moors, thereby completing the Reconquista. Portugal had during the 15th century – particularly under Henry the Navigator – gradually explored the coast of Africa, and in 1498, Vasco da Gama found the sea route to India. The Spanish monarchs met the Portuguese challenge by financing the expedition of Christopher Columbus to find a western sea route to India, leading to the discovery of the Americas in 1492.
Try to answer this question if possible: Which explorer discovered a sea-route to India?
Answer: Vasco da Gama
Question: Renewable energy commercialization involves the deployment of three generations of renewable energy technologies dating back more than 100 years. First-generation technologies, which are already mature and economically competitive, include biomass, hydroelectricity, geothermal power and heat. Second-generation technologies are market-ready and are being deployed at the present time; they include solar heating, photovoltaics, wind power, solar thermal power stations, and modern forms of bioenergy. Third-generation technologies require continued R&D efforts in order to make large contributions on a global scale and include advanced biomass gasification, hot-dry-rock geothermal power, and ocean energy. As of 2012, renewable energy accounts for about half of new nameplate electrical capacity installed and costs are continuing to fall.
Try to answer this question if possible: As of 2012, what accounts for about half of new nameplate electrical capacity?
Answer: renewable energy
Question: The tram system that now criss-crosses the historic city centre complements walking and biking in it. The centre has been transformed into a pedestrian priority zone that enables and invites walking and biking by making these active modes of transport comfortable, safe and enjoyable. These attributes are accomplished by applying the principle of "filtered permeability" to the existing irregular network of streets. It means that the network adaptations favour active transportation and, selectively, "filter out" the car by reducing the number of streets that run through the centre. While certain streets are discontinuous for cars, they connect to a network of pedestrian and bike paths which permeate the entire centre. In addition, these paths go through public squares and open spaces increasing the enjoyment of the trip. This logic of filtering a mode of transport is fully expressed in a comprehensive model for laying out neighbourhoods and districts – the Fused Grid.
Try to answer this question if possible: What system also complements walking and biking? 
Answer: tram
Question: Bohemia prospered in the 14th century, and the Golden Bull of 1356 made the king of Bohemia first among the imperial electors, but the Hussite revolution threw the country into crisis. The Holy Roman Empire passed to the Habsburgs in 1438, where it remained until its dissolution in 1806. Yet in spite of the extensive territories held by the Habsburgs, the Empire itself remained fragmented, and much real power and influence lay with the individual principalities. In addition, financial institutions, such as the Hanseatic League and the Fugger family, held great power, on both economic and a political levels.
Try to answer this question if possible: In what year did a Silver Bull make the king of Bohemia first among the imperial electors?
Answer:
unanswerable