A preserved oak tree about 3,500 years old found in Riga, Latvia.

The reconstruction of this prominent building fulfilled a long-written command.

The oldest housing complex in Riga is a mini timeline of architectural trends.

Flamboyant architecture from the turn of 20th century.

A black cat protests the City Guild in Riga's Old Town.

This celebration of Latvia’s freedom and independence avoided demolition over half a century of Soviet occupation.

A map store filled with original Cold War era Russian maps of the world.

3,000 market stands in five former Zeppelin hangars.

Double spiral staircases are not unheard of, but they are very rare.

The world's oldest grape-producing vine has survived four centuries of turmoil and even has its own anthem.

This scale model of our solar system hid in plain sight for years before a physics team sought out all the planets.

This 135-year-old weather station studied the effects of the climate on human health.

The first statue to be added to Saint Peter's Square in over 350 years is an ode to migrants and refugees around the world.

One of Hollywood's most iconic actresses was born in an upscale Brussels neighborhood in 1929.

Perhaps the most obscure, simplistic Banksy installation found in Bristol or in the entire world.

This 17th-century passageway is home to numerous bookshops, a witch legend, and the oldest pizzeria in the world.

This shining multicolored metro station deep under Naples is said to be the most beautiful in Europe.

In a city that boasts four separate inclined cable railways, this is one of the busiest funicular lines in the world.

Every day is like Christmas on this street where the traditional Neapolitan nativity scene comes to life.

Italy's "New Mountain" rose from the ground in a volcanic eruption in 1538.

A sulfuric hellscape in southern Italy.

The once forbidden "secret cabinet" of erotic art from excavations of Pompeii and Herculaneum.

A special area of the National Archaeological Museum of Naples is located inside a metro station.

This medieval city gate is now a blend of the past and the modern world.