A large number of international institutions have their seats in Switzerland, in part because of its policy of neutrality. Geneva is the birthplace of the Red Cross and Red Crescent Movement and the Geneva Conventions and, since 2006, hosts the United Nations Human Rights Council. Even though Switzerland is one of the most recent countries to have joined the United Nations, the Palace of Nations in Geneva is the second biggest centre for the United Nations after New York, and Switzerland was a founding member and home to the League of Nations.
There were several border conflicts between Colombia and Peru in the early part of the 20th century, and in 1922, their governments signed the Salomón-Lozano Treaty in an attempt to resolve them. As part of this treaty, the border town of Leticia and its surrounding area was ceded from Peru to Colombia, giving Colombia access to the Amazon River. On 1 September 1932, business leaders from Peruvian rubber and sugar industries who had lost land, as a result, organised an armed takeover of Leticia. At first, the Peruvian government did not recognise the military takeover, but President of Peru Luis Sánchez Cerro decided to resist a Colombian re-occupation. The Peruvian Army occupied Leticia, leading to an armed conflict between the two nations. After months of diplomatic negotiations, the governments accepted mediation by the League of Nations, and their representatives presented their cases before the Council. A provisional peace agreement, signed by both parties in May 1933, provided for the League to assume control of the disputed territory while bilateral negotiations proceeded. In May 1934, a final peace agreement was signed, resulting in the return of Leticia to Colombia, a formal apology from Peru for the 1932 invasion, demilitarisation of the area around Leticia, free navigation on the Amazon and Putumayo Rivers, and a pledge of non-aggression.
Switzerland lies between latitudes 45° and 48° N, and longitudes 5° and 11° E. It contains three basic topographical areas: the Swiss Alps to the south, the Swiss Plateau or Central Plateau, and the Jura mountains on the west. The Alps are a high mountain range running across the central-south of the country, comprising about 60% of the country's total area. The majority of the Swiss population live in the Swiss Plateau. Among the high valleys of the Swiss Alps many glaciers are found, totalling an area of 1,063 square kilometres (410 sq mi). From these originate the headwaters of several major rivers, such as the Rhine, Inn, Ticino and Rhône, which flow in the four cardinal directions into the whole of Europe. The hydrographic network includes several of the largest bodies of freshwater in Central and Western Europe, among which are included Lake Geneva (also called le Lac Léman in French), Lake Constance (known as Bodensee in German) and Lake Maggiore. Switzerland has more than 1500 lakes, and contains 6% of Europe's stock of fresh water. Lakes and glaciers cover about 6% of the national territory. The largest lake is Lake Geneva, in western Switzerland shared with France. The Rhône is both the main source and outflow of Lake Geneva. Lake Constance is the second largest Swiss lake and, like the Lake Geneva, an intermediate step by the Rhine at the border to Austria and Germany. While the Rhône flows into the Mediterranean Sea at the French Camarque region and the Rhine flows into the North Sea at Rotterdam in the Netherlands, about 1000 km apart, both springs are only about 22 km apart from each other in the Swiss Alps.

Question: What is the largest lake in the country that headquartered the organization that intervened in border conflicts between Colombia and Peru with mediation for the governments?
Answer: Lake Geneva