1. United States: The United States declared neutrality at the outbreak of war in 1914. However, it gradually abandoned its neutral stance as the war progressed. The US began providing financial aid to the Allied Powers in 1915, and it entered the war on the side of the Allies in 1917.
2. Spain: Spain declared neutrality at the outbreak of war, and it remained neutral throughout the conflict. Spain's neutrality was largely due to its internal instability and economic problems.
3. Switzerland: Switzerland declared neutrality at the outbreak of war, and it remained neutral throughout the conflict. Switzerland's neutrality was based on its long-standing policy of neutrality and its role as a host country for international organizations.
4. Netherlands: The Netherlands declared neutrality at the outbreak of war, and it remained neutral throughout the conflict. The Netherlands' neutrality was largely due to its small size and its vulnerability to attack from both sides.
5. Sweden: Sweden declared neutrality at the outbreak of war, and it remained neutral throughout the conflict. Sweden's neutrality was largely due to its geographical isolation and its dependence on trade with both sides.
6. Norway: Norway declared neutrality at the outbreak of war, and it remained neutral throughout the conflict. Norway's neutrality was largely due to its small size and its vulnerability to attack from both sides.