Try to gain more land.
It didn't gain any land. It did lose a lot of land, though.
The USA joined World War I after the Germans sank the Lusitania, a British cruise-liner, containing hundreds of Americans. Their entrance is similar to Belgium's, as they were attacked by Germany. Other countries entered the war for reasons of alliances or reasons of wanting to gain land.
Germany entered WWI because they were allies with Austria-Hungary and Russia. Austria-Hungary went to war because of the assassination of the arch duke Franz Ferdinand and Germany saw that as a good opportunity to attack France and try to gain land.
After World War I, Denmark gained the territories of North Schleswig from Germany following a plebiscite held in 1920. The region, also known as Sønderjylland, had been part of Germany since the Second Schleswig War in 1864. The plebiscite allowed residents to vote on whether to join Denmark or remain with Germany, resulting in the majority choosing to join Denmark. This territorial gain was part of the post-war adjustments outlined in the Treaty of Versailles.
There goals where to become a world power.
Germany
Germany declared war on Poland. Poland didn't have a choice.
The United Kingdom officially declared war on Germany on August 4, 1914, thereby entering World War I.
Austria had been annexed by Germany in March 1938.
Try to gain more land.
Germany sent Mexico a document trying to get them to declare war on the USA and thereby prevent USA from entering the war on the side of the Allies. The British intercepted the document and after they showed it to the Americans, the USA declared war on Germany, entering WWI.
Brilliant leadership, patriotism, and the large population of Germany.
stop
Germany sent the telegram to Mexico in 1917 in an attempt to form an alliance and distract the United States from entering World War I.
To gain support for entering World War II - Apex
It didn't gain any land. It did lose a lot of land, though.