What were the problems of the late Middle Ages, and how did Europe recover from them?

Is this world war 2?

The plague came to Europe from the East, most probably via the trade routes known as the Silk Road overland, and certainly by ship oversea. The Black Death – a combination of bubonic, septicemic, and pneumonic plague (and also possibly a strain of murrain) – had been gaining momentum in the East since at least 1322 CE and, by c. 1343 CE, had infected the troops of the Mongol Golden Horde under the command of the Khan Djanibek (r. 1342-1357 CE) who was besieging the Italian-held city of Caffa (modern-day Feodosia in Crimea) on the Black Sea

Explanation:

in the 1800s, chinese workers migrated to the united states, first to work in the gold mines, but also to take agricultural jobs, and factory work, especially in the garment industry. chinese immigrants were particularly instrumental in building railroads in the american west, and as chinese laborers grew successful in the united states, a number of them became entrepreneurs in their own right. as the numbers of chinese laborers increased, so did the strength of anti-chinese sentiment among other workers in the american economy. this finally resulted in legislation that aimed to limit future immigration of chinese workers to the united states, and threatened to sour diplomatic relations between the united states and china.