The system of passports as we know it today dates from roughly a hundred years ago, when leading world powers were trying to figure out a way to regulate international travel in the messy aftermath of World War One. Ever since, these documents have been seen both as boarding passes to freedom and as levers for government control. But which of the world's passports open up the widest vistas of international travel? The Henley Passport Index has an answer. For 199 passports, it tallies up the number of countries that are accessible without obtaining a prior visa. Here's a heat map of which countries' passports are the most powerful right now.

In 1990, the two parts of Germany reunited in a process whereby the much wealthier West absorbed the East. After decades of separation there were cultural divergences as well as economic ones. In the years since, the gaps between east and west have closed substantially, but in many ways they persist. Here's a look at a few different ways in which that's true.

The US is opening a national security investigation into TikTok, the wildly popular short-form lip-syncing and music video app that already has more than 500 million users. Why? Because TikTok is owned by a Chinese company called ByteDance. Lawmakers are worried about how that company handles the data it gathers on its 26 million US-based users, most of whom are under 25 years old. All those users produce reams of valuable personal data that Bytedance can use to improve its AI algorithms, but the Chinese government's broader AI and data ambitions have also become a national security concern for US spooks. As the alarm bells sound in Washington over yet another Chinese tech company, here's a look at where TikTok is used most, and by whom.

Americans' views on trade have ebbed and flowed over the past few decades, influenced in part by trade milestones like the signing of the North American Free Trade Agreement (NAFTA) or China's entry into the WTO. But in recent years, a strong and growing majority of Americans see foreign trade, in principle, more as an opportunity than as a threat. Here's a look at the data from 1992-2019.