Exercitando

<table>
                <thead>
                    <tr>
                        <th>Dia</th>
                        <th>Horário</th>
                    </tr>
                </thead>

                <tbody>
                     <tr>
                        <td>Segunda</td>
                        <td>8h ~ 20h</td>
                    </tr>
                    <tr>
                        <td>Quarta</td>
                        <td>8h ~ 20h</td>
                    </tr>
                    <tr>
                        <td>Sexta</td>
                        <td>8h ~ 20h</td>
                    </tr>

                    <tr>
                        <td colspan="5">Rio de Janeiro</td> 
                    </tr>
                </tbody>
            </table>

table {
    margin: 20px 0 40px;
}

thead {
    background: #555555;
    color: white;
    font-weight: bold;
}

td, th {
    border: 1px solid #000000;
    padding: 8px 15px;
}