Title: Railway electrification system.
Question: What was the solution for the return current problem in Paris Metro?

Title: Tajikistan.
Question: Who controled the Tajikistan portion of Russian Trukestan?

Title: Queen Victoria.
Question: Who was Victoria's last surviving uncle?

Title: North Carolina.
Question:
In the 16th century, where did Spanish explorers meet Mississipian cultureal people?